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Best SIP Trunk Providers 2026: 10 Compared on Price, Support and PBX Fit

Ten SIP trunking providers US businesses actually shortlist, compared on what changes your bill and your uptime: per-minute rates, channel fees, contracts, support model and how each one behaves with Asterisk, FreePBX, 3CX and contact-center platforms.

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Comparison · · Updated · 13 min read

How We Compared SIP Trunk Providers

A SIP trunk is a commodity until something breaks or the bill arrives. So we scored providers on the things that actually differ between them:

  • Pricing model and transparency. Published rates or quotes? Per minute, per channel, or per user? Any setup fees, minimums or surcharges?
  • Channel fees and capacity. Do you pay for concurrent-call paths whether you use them or not, and what happens on your busiest day?
  • Contracts. Month-to-month, or a term that outlives your needs (see what happened to Lumen customers below).
  • Support model. Phone with a human, ticket queue, or wiki and forums. This decides how long an outage lasts.
  • PBX fit. Registration and IP authentication, TLS/SRTP, STIR/SHAKEN attestation, E911 with dispatchable location, documented configs for Asterisk, FreePBX, 3CX, Cisco and Avaya.
  • Track record. Years in the business and whether voice is the core product or a side line that could be discontinued.

SIP Trunk Providers Compared (2026)

ProviderInbound (US)Outbound (US)Local numberChannel feesContractSupport
1. IPComms$0.009/min$0.010/min$1.50/mo$0 per channelNoneUS phone + email, all customers
2. Twilio Elastic SIP Trunking$0.0085/min$0.014/min$1.00/mo$0 per channelNoneTicket; phone on enterprise tiers
3. Telnyx~$0.005-0.01/min~$0.005-0.01/min~$1.00/mo$8-12/mo per channel optionNoneTicket and docs
4. BandwidthCustom quoteCustom quoteCustom quoteCustom quoteAnnual commitments typicalTiered by contract
5. Flowroute~$0.012/min~$0.0098/min~$1.39/mo$0 per channelNoneTicket-based
6. VoIP.ms~$0.009/min~$0.009/min$0.85/mo$0 per channelNoneWiki, forums, email ticket
7. SIP.USIncluded in channel feeIncluded in channel fee$1.00/mo$24.95/channel (unlimited)NoneEmail and portal
8. ClearlyIP~$0.009/min~$0.010/min~$1.00/mo$0 per channelNoneTicket-based
9. Vonage BusinessIncluded (bundled)Included (bundled)Included in planPer line/user1-3 year contractsVaries by tier
10. NextivaMetered or bundledMetered or bundled1 per user, extras costPer user (UCaaS)Annual/multi-year for best priceAll plans

Where a provider quotes rather than publishes, the table says so. Approximate figures (~) are the ranges published for typical US domestic traffic.

The 10 Best SIP Trunk Providers, Reviewed

1. IPComms — Best overall for PBX trunking

Established 2002 · Inbound $0.009/min · Outbound $0.010/min · Numbers $1.50/mo · Channels: $0 per channel · Contract: None

IPComms has sold SIP trunking to US and Canadian businesses since 2002 and still does only that: trunks, numbers, toll-free and hosted PBX on its own carrier-grade switching with East and West points of presence. Pricing is published and simple: $0.009/min inbound, $0.010/min outbound, local numbers $1.50/mo, $0 per channel with no set concurrent-call limit, no contract. TLS/SRTP, STIR/SHAKEN signing, E911 with dispatchable location and failover routing are included; porting is handled for you at $5 per number.

Trade-offs: it is a specialist, not a CPaaS, so there is no programmable-voice API on the scale of Twilio, and international coverage is narrower than the carriers built for it. If you run Asterisk, FreePBX, 3CX, Cisco or Avaya and want a human on the phone, it is the one to test first.

Pros
  • $0 per channel, no set call limits
  • Published per-minute pricing, no contracts
  • US-based support from SIP engineers, every plan
  • Since 2002; TLS/SRTP, STIR/SHAKEN, E911 included
Cons
  • No programmable-voice API platform
  • Smaller international footprint than the CPaaS carriers

See IPComms pricing

2. Twilio Elastic SIP Trunking — Best for developers

Established 2008 · Inbound $0.0085/min · Outbound $0.014/min · Numbers $1.00/mo · Channels: $0 per channel · Contract: None

Twilio's trunking product sits on the same platform as its voice, messaging and video APIs, which is the point: if your team writes code, you can build IVRs, call flows and recording pipelines around the trunk. Elastic capacity scales automatically and coverage is global.

For a plain PBX trunk it is expensive per outbound minute and the support model assumes you read docs and open tickets. Choose it when the trunk is one part of a software product, not when you need someone to talk a phone-system admin through a registration problem.

Pros
  • Best-in-class APIs and documentation
  • Elastic capacity, global reach
  • No contracts
Cons
  • Highest outbound rate on this list
  • Support is ticket-based unless you are enterprise
  • Configuration assumes technical staff

IPComms vs Twilio

3. Telnyx — Best API + SIP hybrid

Established 2013 · Inbound ~$0.005-0.01/min · Outbound ~$0.005-0.01/min · Numbers ~$1.00/mo · Channels: $8-12/mo per channel option · Contract: None

Telnyx owns a private global IP network and offers both classic SIP trunks and programmable voice from one Mission Control portal. Per-minute rates are among the lowest published, and channel-based plans exist for predictable bills.

The portal can overwhelm non-technical admins and support is primarily ticket-driven. A strong choice for tech-savvy companies and MSPs that want API control alongside conventional trunks.

Pros
  • Own private network
  • Low per-minute rates, both usage and channel models
  • API and portal in one place
Cons
  • Steep learning curve for PBX-only admins
  • Support mostly asynchronous

IPComms vs Telnyx

4. Bandwidth — Best for enterprise wholesale

Established 1999 · Inbound Custom quote · Outbound Custom quote · Numbers Custom quote · Channels: Custom quote · Contract: Annual commitments typical

Bandwidth is a Tier 1 CLEC that owns its network and quietly carries traffic for many well-known UCaaS brands. Enterprises with very high volumes get direct carrier access, aggressive negotiated rates and real SLAs.

Nothing is self-service: pricing is quote-only, onboarding runs weeks, and minimum volumes are typical. Small and mid-size businesses generally cannot get an account, and should not try.

Pros
  • Tier 1 carrier, owns the network
  • Enterprise SLAs and number-management APIs
Cons
  • No published pricing, sales-led
  • Annual commitments and volume minimums
  • Not practical below enterprise scale

IPComms vs Bandwidth

5. Flowroute — Best for pure usage billing

Established 2007 (Intrado) · Inbound ~$0.012/min · Outbound ~$0.0098/min · Numbers ~$1.39/mo · Channels: $0 per channel · Contract: None

Flowroute pioneered no-channel, pay-per-minute trunking and still does it well, with a clean portal, good documentation and a solid record with Asterisk and FreePBX deployments. It is now part of Intrado.

Inbound is pricier than most on this list and support is ticket-only, so budget time for self-service troubleshooting.

Pros
  • No channel fees, usage-only billing
  • Mature portal and docs
  • Strong PBX compatibility
Cons
  • Higher inbound rate
  • No phone support

IPComms vs Flowroute

6. VoIP.ms — Best budget option for technical users

Established 2007 · Inbound ~$0.009/min · Outbound ~$0.009/min · Numbers $0.85/mo · Channels: $0 per channel · Contract: None

VoIP.ms is the hobbyist-turned-small-business favourite: very low rates, numbers from under a dollar, dozens of points of presence and a wiki that documents every PBX ever made. Prepaid, no contracts.

There is no phone support at all, and outages are handled through status pages and forums. Fine for a technical owner-operator; risky for a business that needs someone to call when the phones stop.

Pros
  • Lowest number and minute prices here
  • Huge community documentation
  • Many PoPs
Cons
  • No phone support
  • Self-serve troubleshooting only
  • Prepaid balance management

IPComms vs VoIP.ms

7. SIP.US — Best flat-rate channel pricing

Established 2005 · Inbound Included in channel fee · Outbound Included in channel fee · Numbers $1.00/mo · Channels: $24.95/channel (unlimited) · Contract: None

SIP.US sells unlimited-calling channels at a flat monthly fee, which makes budgeting trivial for offices with steady, heavy calling on a known number of concurrent lines.

Flat channels cost more than usage billing once you size for peak hour, and adding capacity means buying another channel. Good for predictable, high-utilisation lines; poor value for bursty or light traffic.

Pros
  • Predictable flat bill
  • Unlimited domestic calling per channel
  • No contracts
Cons
  • Pay for peak capacity every month
  • Capacity changes are a purchase, not automatic

IPComms vs SIP.US

8. ClearlyIP — Best for FreePBX shops

Established 2019 · Inbound ~$0.009/min · Outbound ~$0.010/min · Numbers ~$1.00/mo · Channels: $0 per channel · Contract: None

Founded by former Sangoma/FreePBX people, ClearlyIP sells trunks that are tightly integrated with FreePBX through its own module, plus phones and hosted PBX. Rates are competitive and there are no channel fees.

It is a young company with ticket-based support, and the integration advantage only matters if you run FreePBX.

Pros
  • FreePBX module integration
  • Competitive usage pricing
  • No contracts
Cons
  • Newer company
  • Ticket support only

IPComms vs ClearlyIP

9. Vonage Business — Best if you already run Vonage UCaaS

Established 2001 (Ericsson) · Inbound Included (bundled) · Outbound Included (bundled) · Numbers Included in plan · Channels: Per line/user · Contract: 1-3 year contracts

Vonage offers SIP trunking as an adjunct to its unified-communications suite. If your seats, meetings and messaging already live there, the trunk integrates cleanly.

As a standalone trunk it is per-line pricing with multi-year contracts, which is the model SIP trunking was supposed to replace. Support quality has been uneven since the Ericsson acquisition.

Pros
  • Fits an existing Vonage UCaaS deployment
  • Enterprise brand recognition
Cons
  • Per-line pricing, 1-3 year terms
  • SIP trunking is not the core product

IPComms vs Vonage

10. Nextiva — Best all-in-one for non-technical teams

Established 2006 · Inbound Metered or bundled · Outbound Metered or bundled · Numbers 1 per user, extras cost · Channels: Per user (UCaaS) · Contract: Annual/multi-year for best price

Nextiva is a UCaaS provider first: phones, apps, meetings and a support team on every plan. SIP trunking is available for customers who keep their own PBX, priced per user rather than per minute.

You pay for a bundle whether or not you use it, and the best prices require annual or multi-year terms. Pick it for the whole package, not for the trunk.

Pros
  • Phone support on all plans
  • Complete UCaaS bundle
Cons
  • Per-user pricing, contracts for best rates
  • Trunking is a side product

IPComms vs Nextiva

Building this? Your PBX will need a number

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Local numbers $1.50 a month, toll-free $2.00, $1.00 one-time setup. Pick one here and it carries into signup.

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More numbers, porting and E911 in the portal

Outbound US and Canada
$0.010 /min
Inbound
$0.009 /min
Local number
$1.50 /mo
Per channel
$0 no set limits

Sign up now or see the full rate table. No contracts.

Best SIP Trunk Provider by Use Case

Asterisk, FreePBX, 3CX or another PBX you run

IPComms, then Flowroute or ClearlyIP. Usage billing, no channel fees, documented configs. Setup: Asterisk PJSIP, FreePBX, 3CX.

Call centers and bursty volume

A provider with no per-channel cap so seasonal peaks do not need a change order: IPComms or Twilio. Read SIP trunking for call centers and capacity planning.

Developers building voice into software

Twilio for the ecosystem, Telnyx for lower rates with a private network.

Predictable flat bill, steady heavy calling

SIP.US unlimited channels, if utilisation is high enough to beat usage pricing.

Enterprise wholesale volume

Bandwidth, if you have the volume and the procurement patience for a quote-driven carrier.

No PBX, want everything hosted

A UCaaS bundle (Nextiva, Vonage, RingCentral, 8x8) or a hosted PBX with per-minute trunking behind it.

Leaving Lumen or CenturyLink

Lumen ended new voice sales on August 1, 2026. Any usage-priced provider above replaces the trunk without touching your PBX; start before your term rolls to month-to-month. Lumen migration guide · IPComms vs Lumen.

How to Choose: Seven Questions to Ask Any Provider

  • What is the all-in cost for my numbers plus my last three months of minutes? Get it in writing, including taxes and USF.
  • Is there a per-channel fee or a concurrent-call cap? What happens at cap: busy signal or overflow?
  • Month-to-month, or a term? What is the early-termination fee?
  • Who do I call at 2 a.m., and is that included or an upsell?
  • Do you support TLS and SRTP, sign calls with STIR/SHAKEN full attestation, and provision E911 with dispatchable location per number?
  • How many points of presence, and how does my PBX fail over between them (DNS SRV, secondary registration, IP list)? See {a('/blog/sip-trunk-failover/','SIP trunk failover')}.
  • Will you handle the port, including toll-free RespOrg changes, and what is the fee per number?

Then test. Every usage-priced provider on this list lets you stand up a trunk with a temporary number and make real calls before you port anything; our trunk testing guide shows what to check.

Switching SIP Trunk Providers Without Downtime

Add the new provider as a second trunk on your PBX, route outbound test calls through it for a few days, register E911 for each number, then port numbers in batches with a firm date. Inbound follows the port automatically; run both trunks in parallel until the last number has moved, then close the old account. Detailed steps in how to port numbers to a SIP trunk.

Frequently Asked Questions

Who is the best SIP trunk provider for small business?
For a small business running its own PBX, the best value comes from usage-priced providers with no channel fees and human support: IPComms is our pick because the price is published ($0.009/min inbound, $0.010/min outbound, $1.50/mo per number, $0 per channel), there is no contract, and support is a US phone call. VoIP.ms is cheaper on paper but has no phone support; Flowroute and ClearlyIP are solid ticket-supported alternatives.
How much does a SIP trunk cost per month?
With usage-priced providers there is no monthly trunk fee at all: you pay for numbers (about $1 to $1.50 each) and minutes (about a cent). A 10-line office with 5,000 outbound and 3,000 inbound minutes pays about $92 a month with IPComms. Channel-priced providers charge $8 to $25 per concurrent call path per month regardless of use, and UCaaS bundles run $15 to $35 per user.
What is the difference between a SIP trunk provider and a UCaaS provider?
A SIP trunk provider connects a phone system you control (Asterisk, FreePBX, 3CX, Cisco, Avaya) to the public network and bills for numbers and minutes. A UCaaS provider (RingCentral, 8x8, Nextiva, Vonage Business) hosts the phone system itself and charges per user. If you already own a PBX, a trunk is a fraction of the cost; if you want no PBX at all, look at UCaaS or a hosted PBX.
Which SIP trunk providers work with Asterisk and FreePBX?
All ten providers here support standards-based SIP registration or IP authentication, so any of them will trunk to Asterisk or FreePBX. IPComms, Flowroute, VoIP.ms, ClearlyIP and Telnyx publish PJSIP configuration guides and are the most common pairings; ClearlyIP has a FreePBX module. See our Asterisk PJSIP trunk setup guide for the configuration.
Do I have to sign a contract for SIP trunking?
Not with the specialist providers. IPComms, Twilio, Telnyx, Flowroute, VoIP.ms, SIP.US and ClearlyIP are month-to-month. Bandwidth typically requires annual commitments, and UCaaS-style providers such as Vonage and Nextiva reserve their best pricing for one- to three-year terms.
Can I keep my phone numbers when I change SIP trunk providers?
Yes. US local and toll-free numbers are portable under FCC rules; the new provider submits the port to the old one and the number moves on a scheduled date, usually within 7 to 14 business days for local numbers. Do not cancel the old service first, because a disconnected number cannot be ported.
What about Lumen and other carriers leaving the SIP trunking market?
Lumen stopped selling SIP trunking, Voice Complete and hosted Teams voice on August 1, 2026, and existing contracts roll to month-to-month at term with nothing to renew into. If you are on Lumen or CenturyLink SIP, start evaluating providers on this list six to twelve months before your term ends. Our Lumen migration guide covers the timeline and porting steps.
How many concurrent calls does a SIP trunk support?
It depends on the provider's model. Channel-priced trunks support exactly the number of channels you buy. Usage-priced trunks from IPComms, Twilio, Flowroute or VoIP.ms have no fixed channel count: capacity follows your traffic and your PBX's own limits, which is why they suit seasonal or bursty call volumes.

Stop worrying about SIP trunk capacity. We have you covered.

SIP trunking from a US carrier since 2002: $0.009 per minute inbound, $0.010 outbound, numbers from $1.50 a month, $0 per channel, no contracts.

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