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Best SIP Trunking Providers

June 20, 2018

11:15 am

What is SIP Trunking? Session Initiation Protocol (SIP) – or “SIP Trunking”, as it is commonly known – is a phone system feature that is frequently accompanied with VoIP phone systems to providing optimal call quality and consistency.

VoIP phone setups are far cheaper and more flexible than traditional lines, and SIP trunking provides a dedicated connection to the Public Switched Telephone Network (PSTN) to ensure internet-based calls can be made just as reliably.

“Trunking” is a term that was used in the early days of the telephone service. A trunk was a way in which large numbers of users could share a communications path. SIP Trunking today is just one of the protocols offered by VoIP providers, as VoIP is fast becoming the global business standard.

This guide will examine the best SIP Trunking providers to choose for your business, as well as a number of areas related to Session Initiation Protocol (SIP). This includes more detail on exactly what SIP is, how it works, and a SIP price comparison so you can ensure you’re getting the best solutions for your budget.

If you're here looking for the best business phone system for your company, then use our comparison form today to get quotes tailored to your own needs.

On this page:

Top 10 Best SIP Provider Reviews

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ProviderPrice FromOur RatingHighlightCompare
Vonage logoVonage$35.99/mo5 starsPBX integrationget-quote-button-green
Nextiva LogoNextiva$24.95/mo5 starsAutomatic call reroutingcompare-now-button-white
bandwidth logoBandwidth$0.0055/min5 starsE9-1-1 across the USget-quote-button-green
Twilio logoTwilio$0.007/min5 starsCustomer satisfactioncompare-now-button-white logoSIP.US$24.95/mo4.5 starsFraud protectionget-quote-button-green
Voxbone logoVoxbone$500/mo4.5 starsGreat uptimecompare-now-button-white
Alliance Phones logoAlliance Phones$19.97/mo4 starsOffers call analyticsget-quote-button-green
megapath logoMegaPath$19.95/mo4 starsKeep existing phonescompare-now-button-white
8x8 Logo8×8$24.99/mo4 stars7,000 rate centers in USget-quote-button-green
net2phone logoNet2PhoneOn Request4 starsNo contract necessarycompare-now-button-white

SIP providers operate by supplying businesses with a trunk that links your PBX to the PSTN. SIP trunking replaces the need for a traditional telephone trunk, and lets you streamline your telecom services.

SIP trunks combine data, voice and video in one line, eliminating the need for individual physical lines and media.  While all SIP trunking performs the same function, some providers connect the IP PBX virtually. Hosted or cloud-based carriers offer built-in PSTN connections, meaning your business doesn’t have to purchase trunks separately.

Rather, the provider hosts all of the services on its own servers, and allows you to use them.

While some providers offer free SIP trunking, the quality of these services is inconsistent. Businesses that require a reliable IP voice experience should instead consider one of the following providers:

Our Top Ten:

Vonage Logo

1. Vonage

Editor Rating: 5 stars

  • No Annual Contracts
  • Excellent Support
  • Free Trial

Hosted through PBX, Vonage is a business VoIP provider offering both affordable and reliable solutions for businesses. Ideal for companies that employ 50 staff or fewer, the company is a market leader in VoIP solutions for all types of business. Vonage owns its own software – an advantage it holds over some of the other providers – which means it can offer a higher level of quality with its SIP services.

Pricing is charged on a monthly basis, but customers aren’t locked in to long term contracts – something which always appeals to the budget conscious business. This SIP provider offers a number of advanced features, with an easy to navigate interface, first class customer support, and dedicated customer service when you need it.

Nextiva Logo

2. Nextiva

Editor Rating: 5 stars

  • Unlimited Calls
  • Use Existing Structure
  • Simple No-Fee Setup

Nextiva offers businesses a range of SIP trunking options which are designed to save money on business communications. By routing through Nextiva's SIP trunk, businesses can benefit from unlimited local and long distance calling features, without changing their existing PBX equipment.

With this service, any traditional phone system can be quickly converted into a dedicated IP based system to manage communications, and calls can be auto-rerouted to alternate numbers if needed. The company offers an unlimited contract starting at $24.95 per month, which includes everything you need to set up and run a fully functioning communications system. Nextiva also offers a metered plan that starts from a flat $14.95, and adds $0.008 per minute used. We'd recommend the unlimited plan, as the minutes can add up quickly. Either one includes a free trial.

bandwidth logo

3. Bandwidth

Editor Rating: 4.5 stars

  • Toll-free support
  • Inbound caller ID/location
  • Multiple pricing models

Bandwidth offers a SIP trunking service that covers domestic and international long distance calls. Its also comes with white page listing included, lets users view caller ID and locations on inbound calls, and comes with both types of pricing plans. The service charges a metered plan that costs $0.0055 per minute for inbound calls and $0.01 per minute for outbound, plus a flat $0.35 per phone line per month. Custom enterprise prices are available with a consultation.

Bandwidth also offers enhanced 9-1-1 support (E9-1-1). This automatically identifies the location of anyone calling 9-1-1, routing the call to the nearest local Public Safety Answering Point and relaying location to the responder to ensure the fastest emergency response. Bandwidth is one of just a few providers to offer E9-1-1 coverage across the entire US.

Twilio logo

4. Twilio

Editor Rating: 4.5 stars

  • Global reach, local presence
  • Redundant routing
  • Flexible pricing

Twilio offers quick access across the globe, while providing the prefix coverage a business needs to retain its recognizable local area code. An additional benefit offered by this SIP trunking service is the reliability of an effectively redundant, carrier grade VoIP network of Tier 1 carriers across over 100 countries. Twilio charges $0.007 per minute for toll-free numbers in the US, and between $0.007 and $0.25 per minute for extended zones, depending on the zone.

Twilio offers a stand-out customer support team, and includes Twilio Voice Insights tools with its service. These tools allow businesses to better parse data on their call performance by drawing out insights from details like packet loss, jitter, or PDD.

Sip.US logo


Editor Rating: 4.5 stars

  • Reliable Support
  • Fraud Protection
  • Simple Pricing Structures

SIP.US puts the user in control of its SIP trunk services for IP PBX systems and analog-digital telephone adapters. Rather than locking customers in to a corresponding bandwidth plan, SIP.US lets you use your preferred bandwidth supplier.

Additionally, the company provides an easy-to-use, self-managed interface where you can add or change service, as well as review call data records. For a trunk with unlimited capacity, SIP.US charges $24.95 per channel (i.e., per line). Its phone number pricing amounts to $1.00 per month in the continental US, with international numbers starting at $5.00 per number per month.

SIP.US is easy to manage and offers excellent customer service.

Voxbone logo

6. Voxbone

Editor Rating: 4.5 stars

  • Reliable coverage
  • Easy number porting
  • 24/7 support

Voxbone offers a fully redundant, Tier 1 network of national operators covering over 60 countries, and delivers great uptime to its customers. Voxbone offers three main plans: Starter costs $500/month, Growth is $2,500/month, and Scale Up is $5,000/month. While these prices seem much higher than most of the ranges listed on this page, they offer unlimited minutes within the channel limit, even when calls are concurrent – saving businesses from buying multiple trunks. Voxbone is best for businesses with call capacity needs that can vary, but who still want a fairly predictable overall monthly cost.

Setup costs are an additional charge, and the service doesn't prorate its plans – so you may want to wait until the beginning of the month to upgrade. However, Voxbone's range and reliability are hard to beat, and its 24/7 support team has a track record of prompt responses.

Alliance Phones logo

7. Alliance Phones

Editor Rating: 4 stars

  • Call forwarding
  • Call analytics
  • HD voice quality

Alliance Phones' most popular plan is its unlimited monthly model, which charges $19.97 per month and includes unlimited minutes across the US and Canada. The service also offers a metered plan that charges $0.0081/min after an initial $9.97 monthly fee.

For their money, users can expect the HD voice, call forwarding and number porting features offered by most VoIP services, as well as more rare call analytics tools that can display an operation's call usage in graphs. Customers are not charged setup fees or given annual contracts. A reliable and cost-effective choice for businesses that aren't making calls outside of the US and Canada.

megapath logo

8. MegaPath

Editor Rating: 4 stars

  • Free Installation
  • Great Prices
  • Increase Network

MegaPath allows businesses to streamline IT management through the combination of voice and internet access while reducing costs. The plans offered by MegaPath allow customers to purchase what they need which is based on the calls that your business will process.

Broadband can be purchased from the company or you can integrate the system with your own broadband provider. The system also comes with a router/IAD to support QoS, security and quality monitoring to ensure the best call standards. What’s more, with MegaPath you can use your existing telephone equipment and IP network which enables businesses to save costs. Calling plans start at 500 minutes per month and you can carry over any allowances you haven’t used to the following month.

8x8 Logo

9. 8×8

Editor Rating: 3.5 stars

  • Keep Existing Phones
  • Inbound/Outbound Service
  • Toll-Free

8×8’s SIP trunk uses a VoIP dial tone solution that can be scaled to the needs of businesses large and small. The service provides free calling between 8×8-enabled systems, and emphasizes its pay-as-you-grow scalability. It also offers a variety of service plans, all based on 6-second billing increments.

As a leading name in digital communications and with 7,000 rate centers nation-wide, 8×8’s SIP trunking is reputable, and best suited for companies who may experience fluctuations in growth.

Net2Phone Logo

10. Net2Phone

Editor Rating: 3.5 stars

  • Cut Costs
  • PBX Integration
  • No Activation

Net2Phone’s SIP trunking service allows businesses to take advantage of international DIDs (phone numbers) from over 50 countries.

Meanwhile, it supports unlimited concurrent calls, and offers a no-strings-attached pricing plan. The company offers free use of channels and no monthly contracts.

Net2Phone’s SIP trunking works well for businesses that have a heavy international call volume, and require the freedom of scalability.

Choosing the right SIP Provider

Office phone calling
Once you have researched SIP Trunking sufficiently and you have decided it is the most suitable option for your company, the next important step is to determine the best provider for this service. Look at all providers carefully to see how each of them meets the requirements of your business and whether their solutions fit in with what you need to run the business effectively.

There are many things to take into consideration before you settle on a SIP provider including;

    • Server – It is important to determine whether the provider uses their own networks to deliver the SIP service or whether they use a third party
    • Security – Always a concern for every business owner, calls that you make and receive over the internet must be secure. Check with the provider what security features they have in place to keep your calls secure. As a minimum you should ensure that the provider offers a secure SIP trunking solution featuring anti-fraud systems and protected networks in place as well as active risk monitoring so any security issues can be quickly identified and resolved
    •  Porting – If you decide to leave the company for whatever reason check that it offers the facility to port your number to a new provider
    • Customer Service – There is nothing worse than using a provider who has poor customer service or technical support that is seriously lacking. Although SIP trunking is great at rerouting calls when something does go wrong, make sure that you can contact your provider quickly. Find out how you can contact them, their opening hours and whether they have any out of hours customer service support if you need it.

SIP Trunk Pricing Comparison

You can expect to pay between $20 and $45 per month for an unlimited SIP trunk channel contract. If your vendor uses a pay-as-you-go metered model, expect pricing between $0.006 and $0.02 per minute, with charges varying depending on if it's outgoing/incoming, the destination of the call, and the type of phone number used.

While the metered model might sound like a great deal (who sells anything for less than a cent?), calls can add up fast, and most mid-sized or growing operations should consider the unlimited model first.

The number of SIP trunks your business needs is primarily determined by 2 factors: call volume and internet connection. Industry guidelines dictate that you’ll need roughly 1 SIP trunk for every 2-3 users. This will ensure that your system can support concurrent calls at peak times.

A strong, reliable internet connection also plays an important role. Because SIP trunks use bandwidth, you may need to upgrade your internet package if you think you’ll experience regular, heavy call volume (though this isn’t always necessary).

If you're hoping to start collecting quotes today, try's price comparison form for a quick way to begin the process.

How Does SIP Trunking Work?

The best way to explain what SIP trunking is, is to first explain what it isn’t and the problem it is primarily designed to overcome.

If you’re using a hosted VoIP solution, the next logical step to consider is how  your business premises will be connected to the cloud hosting service. In basic terms, businesses have two options when deciding how they connect to their cloud VoIP service provider:

  1. The simplest option is to route everything through the business’s existing Internet Service Provider – the exact same service you already use to send and receive emails and surf the Web: the obvious benefit here is that the service can be set up without disrupting existing internet services or having to switch providers.

However, the potential downside of routing your business VoIP through the existing network is that because the VoIP call data will have to traverse this additional network in the chain before going to the service providers network, there is an increased chance of connection and call quality issues.

If your LAN (Local Area Network, the data network within your building or office) has limited bandwidth it may not be able to support additional heavy internet usage if you’re integrating your VoIP service into your existing internet plan. The solution is to establish a separate network devoted solely to your VoIP phone activity.

This is where SIP, or Session Initiation Protocol trunking comes in:

  1. SIP trunking is an additional feature offered as part of many business VoIP solutions. A SIP trunk provides a new, dedicated ‘direct line’ to your VoIP service provider (and by extension, your hosted PBX) that bypasses your regular ISP. With a SIP trunk, you no longer need to rely on your regular internet connection for carrying VoIP traffic, ensuring your VoIP network is optimized for call quality and reliability.

SIP Trunking schematic diagram

Unified Communication and telephone services are delivered through SIP trunking using an IP network as a substitute for the normal telephone system. Using SIP trunking a VoIP user is able to make calls to any phone which belongs to a PTSN network without the need for telephone lines. Connections are established using a suitable hosted PBX solution.

There are three elements required for a SIP trunk to function properly. The first is the SIP provider who supplies the service, the second is a phone system with SIP enabled capabilities and thirdly a border element. This border element enables the connection between the enterprise network and the PTSN or an IP network.

The elements are often managed by the SIP trunking provider and they can be either a switch or firewall. Using these three basic components, a business is able to significantly improve its reach in terms of communications. If an IP-PBX has already been installed this will facilitate the process even more.

Advantages of SIP Trunking

SIP phone in office
Businesses can benefit from SIP trunking in a number of ways. They are particularly useful for smaller businesses who want to convey to their customers that they are an established enterprise. For large businesses, having a SIP solution helps because SIP calls are locally based, so customers don’t have to dial an anonymous call center telephone number.

Other benefits include…

Cost savings- When you add a SIP trunk, you eliminate the need for separate PRI connections to your networks. (PRI, or Primary Rate Interface, refers to a physical phone line that only facilitates voice transmissions; it can’t support data). With SIP, you can consolidate your separate voice and data circuits, and purchase only the trunks that you need.

Optimal use of resources- SIP trunks smartly allocate bandwidth to ensure that both voice and data can be supported. Additionally, some providers use voice compression to make efficient use of connections, without compromising call quality.

Room to grow- When a SIP phone system has been set up, businesses can add or remove as many telephone lines as they require without having to pay for more lines than they need, or wait for your telephone provider to add more lines when the business expands.

Maximum flexibility- If you relocate your office you can take your SIP trunking system and phone numbers with you. As the phone lines operate from the internet you are free to move about as you please.

Increased reliability- Trunks located on an analog system can be affected by the weather and depend on costly telephone companies to sort anything out when it goes wrong. SIP trunking avoids any scenario such as this. When a fault occurs the system can reroute the communication to an alternative line and priorities certain phones or networks.

Increased control- All features of a SIP system can be easily controlled through a dedicated web portal, and tailored to meet the specific communication requirements of your business.

Less hardware to manage- Traditional phone systems require lots of hardware which is costly to install and maintain. A SIP trunking system can adapt to your business without having to add any new hardware and adding new lines doesn’t depend on the installation and setup of new devices.

International calling- If you conduct a lot of business overseas, SIP systems are an affordable solution with some providers offering free international calls

Consolidated communications providers- Many IP PBX providers also offer SIP trunks. When the services are combined, the customer can take advantage of a more robust range of voice, data, security and other services. Plus, dealing with only one communications provider is easier than juggling the service requirements of many.

Get SIP Trunking today

SIP trunks are almost a quarter cheaper than the standard PRI trunks. They'll also deliver added flexibility, reliability, and the option to place free voice calls with any other office on the same system.

If you'd like to enhance your business communications, increase call quality and deliver an improved standard of customer service, the first step is to start collecting quotes from the best SIP trunking providers. Just take a minute to fill out's quick and handy quotes form below and you'll be on your way to the perfect SIP trunking service.

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Jack is the Content Manager for He has been writing about a broad variety of technology subjects for over a decade, both in print and online, including laptops and tablets, gaming, and tech scams. As well as years of experience reviewing the latest tech devices, Jack has also conducted investigative research into a number of tech-related issues, including privacy and fraud.