Top 11 Enterprise SIP Trunk Providers Compared for 2025
Legacy telecom stacks weren’t designed to handle today’s pace or global reach. Managing voice infrastructure across global offices, navigating regional compliance, and integrating an evolving list of collaboration platforms gets complicated. And you realize: Traditional voice vendors aren’t cutting it.
Fortunately, enterprise Session Initiation Protocol (SIP) trunking offers centralized voice management, seamless Unified Communications as a Service (UCaaS) and Contact Center as a Service (CCaaS) integrations, and a scalable, secure network for high-quality global calls and dependable uptime.
The need for robust, scalable voice infrastructure is clear. We’ve identified the top enterprise SIP trunk providers of 2025 based on global coverage, reliability, and security to help you choose the right provider.
Enterprise SIP trunking overview
Enterprise SIP trunking replaces the tangle of legacy phone lines and local carriers with a single, IP-based connection for global, scalable voice communications.
Routing calls over the internet earns several SIP trunking benefits, including flexibility, control, and cost efficiency.
SIP isn’t just about voice. It also supports messaging, video conferencing, and customer relationship management (CRM) integrations from a single platform. Businesses migrating to the cloud or consolidating vendors increasingly find that solutions like cloud contact center software and SIP trunking unify communication under one global roof.
The shift from legacy systems to the cloud delivers results, including:
- Increased reliability with 99.999% uptime service level agreements (SLAs)
- Greater flexibility with on-demand provisioning and self-service tools
- Native compatibility with systems like Microsoft Teams, Private Branch Exchange (PBX), cloud PBX, and IP PBX
11 enterprise SIP trunk providers compared
The essentials for enterprise SIP trunking include carrier-grade reliability, expansive global reach, and airtight security that meet your business needs and multinational compliance demands.
| AVOXI | 99.995% uptime SLA | Extensive, 150+ countries | Comprehensive compliance, including CCPA, GDPR, POPIA, HIPAA, PCI-DSS |
| RingCentral | 99.999% (claimed) | 100+ countries | HIPAA, GDPR |
| Twilio | 99.95% (reported) | 100+ countries | SOC 2, ISO 27001 |
| Vonage | 99.99% SLA | 96+ countries | GDPR, HIPAA |
| 8x8 | 99.999% SLA | 50+ countries | SOC 2, ISO 27001 |
| Bandwidth | 99.99% SLA | Primarily the US and Canada, reaching 65+ countries | TLS/SRTP encryption, PCI DSS compliance |
| AT&T Business | Carrier-grade | 200+ countries | FedRAMP, ISO 27001 |
| Verizon | Carrier-grade | 150+ countries | ISO 27001, PCI-DSS |
| Telnyx | 99.999% SLA | 180+ countries | SOC 2, GDPR |
| SIP.US | 99.99% SLA | US-centric | TLS/SRTP encryption |
| Nextiva | 99.999% SLA | Limited international | HIPAA, SOC 2 |
1. AVOXI
AVOXI was built from the ground up to serve enterprise SIP trunking needs globally. With coverage in over 150 countries and a resilient, redundant voice network, AVOXI is perfect for IT leaders who need secure, high-quality voice across continents without juggling local carriers.
AVOXI's elastic SIP trunking model offers unmatched flexibility, ideal for businesses consolidating global telecom or migrating to cloud-native communications platforms like Microsoft Teams, Genesys, or Five9.
Key features:
- Global voice coverage in 150+ countries: Offers extensive international coverage, enabling access to local numbers and globally managed voice services
- Carrier-grade uptime with built-in failover: Redundant routing for consistent call quality
- Secure by design: PCI-DSS, HIPAA, and GDPR compliant with ISO-certified infrastructure
- Seamless UCaaS and CCaaS integration: Native interoperability with major CRMs like Microsoft Teams and Zoom
- Real-time provisioning: Self-service dashboard for instant phone number provisioning and porting
- Enterprise-level APIs: Automated call routing, number management, and easy usage monitoring
Cons:
- Potential learning curve for teams transitioning from legacy PBX systems
- May be more robust than necessary for smaller businesses
2. RingCentral
RingCentral is a well-known name in business communication services, especially in the UCaaS space. Its SIP trunking solution is part of a broader ecosystem, making it appealing to enterprises already using its phone system or video conferencing tools.
Key features:
- Unified communications integration: Integrates SIP trunking with RingCentral's comprehensive UCaaS platform, including messaging and video conferencing
- Global presence: Offers phone numbers and calling plans in numerous countries
- Security features: Employs strong encryption protocols (TLS/SRTP) to secure voice communications
Cons:
- Limited control over underlying SIP configurations
- Offers less extensive global coverage than standalone SIP providers
3. Twilio
Twilio’s programmable SIP trunking appeals to developers and tech-forward companies looking for granular control. It’s highly customizable but requires strong in-house technical capabilities to make the most of its features.
Key features:
- Elastic SIP trunking: Scales capacity in real time based on call volume
- Programmable voice API: Offers extensive APIs for developers to customize and integrate voice functionality
- Global termination and origination support: Provides coverage in 100+ countries
Cons:
- Developer-heavy platform
- Limited support for non-enterprise accounts
4. Vonage
Vonage balances usability and scalability, making it a compelling choice for companies that want a contact center and SIP solution. Following Ericsson's acquisition, Vonage has renewed its focus on global voice services.
Key features:
- UC and CC integration: Connects with Vonage Business Communications and Vonage Contact Center
- Global SIP trunking: Supports local and toll-free numbers in over 100 countries
- Secure voice encryption: Provides Transport Layer Security (TLS) and Secure Real-Time Transport Protocol (SRTP) compliant communications
Cons:
- Regional variation in coverage and features
- Inconsistent support response times
5. 8x8
8x8 is a UCaaS-first company offering SIP trunking as part of its cloud communications platform. Despite its limited global coverage, it performs well for multinational companies in North America and Europe.
Key features:
- End-to-end voice and messaging platform: Fully cloud-based communications stack
- Secure global routing: Compliant with GDPR and other compliance standards
- Call quality monitoring tools: IT teams can troubleshoot voice issues
Cons:
- Smaller global footprint than top-tier SIP providers
- Limited customization options outside the 8x8 ecosystem
6. Bandwidth
As a telecom carrier with direct-to-network access, Bandwidth offers enterprises increased control over their SIP services.
Key features:
- Public Switched Telephone Network replacement: Strong PSTN in the US and Canada
- E911 and emergency services support: Fully compliant for enterprises
- Programmable SIP trunking: Extensive developer tools and voice API
Cons:
- Limited international coverage
- Requires deep technical expertise to implement at scale
7. AT&T Business
As a legacy telecom giant, AT&T offers serious infrastructure and regulatory experience. Its SIP trunking services appeal to large enterprises that need bulletproof uptime and strict compliance.
5. Expert Provider Support
Key features:
- Carrier-grade reliability and reach: Coverage in 200+ countries
- Full PSTN replacement: Built for enterprises transitioning from TDM systems
- Secure call encryption and compliance: Meets FedRAMP and ISO 27001 standards
Cons:
- Sporadically slow onboarding and provisioning
- Pricing and support tailored exclusively for large enterprises
8. Verizon
Verizon’s SIP trunking service leverages its global IP backbone to deliver reliable, high-quality voice services for multinational businesses.
Key features:
- Carrier-grade IP network: Optimized for enterprise voice and video
- Flexible call capacity options: Scales to call volume
- Global number support: Local and toll-free numbers in 150+ countries
Cons:
- Expensive compared to cloud-native providers
- Potentially complex contracts and minimums for users
9. Telnyx
Telnyx offers a self-service approach to SIP trunking with a developer-first mindset. It provides strong performance and automation capabilities, especially for companies with in-house engineering talent.
Key features:
- Full-featured SIP trunking API: Enables programmatic building and management of voice flows
- Tier-1 global network: Owns and operates its infrastructure for better control
- Elastic capacity and call routing: Offers on-demand scalability
Cons:
- Has a smaller support team than legacy carriers
- Technical expertise required for software deployment
10. SIP.US
SIP.US caters to small to medium-sized businesses (SMBs) and resellers and can serve smaller enterprise use cases in the US. It’s known for its fast setup and straightforward pricing.
Key features:
- US-focused SIP trunking: Optimized for North American traffic
- PBX compatibility: Works with FreePBX, Asterisk, and most IP PBXs
- Basic usage analytics: Provides simple reporting tools for admins
Cons:
- Offers limited international coverage
- Minimal support for advanced compliance or security features
11. Nextiva
Nextiva is a solid SIP solution for businesses already in its ecosystem and companies moving upmarket into more robust voice infrastructure.
Key features:
- Native UCaaS integration: Offers built-in unified communications
- Auto attendant and call queues: Scales with team growth
- Basic call analytics: Helps track usage and quality trends
Cons:
- Limited international capabilities
- Lacks some enterprise-grade certifications
How to choose an enterprise SIP trunk provider
Choosing the right SIP trunking provider impacts voice quality, global reach, operational agility, and the ability to integrate into your broader UCaaS and CCaaS ecosystem.
1. Network reliability
SIP trunking’s reliability is only as strong as its network. Look for a provider with redundant, geo-distributed infrastructure and guaranteed uptime SLAs of 99.99% or higher. For business-critical voice traffic, consistent call quality, low latency, and automatic failover support are non-negotiable.
Ensure the provider's reliability is backed by real-time monitoring tools and transparent service reporting.
2. Global coverage
Check if the provider offers local phone numbers in your target markets to reduce long-distance costs and establish a local presence for easier customer contact. Ensure their international network offers sufficient, quality international call routing and complies with regional telecom regulations.
3. Security certifications
Scrutinize the security measures of potential SIP trunk providers and ensure their security aligns with your policies and risk framework.
Check for Systems and Organization Controls 2 (SOC 2), Health Insurance Portability and Accountability Act (HIPAA), and General Data Protection Regulation (GDPR) certifications to ensure adherence to strict security and data privacy standards. Confirm they offer robust encryption protocols like TLS or SRTP to protect voice traffic. And ask about their fraud and anti-eavesdropping safeguards.
4. Scalability
Choose an enterprise SIP trunk provider with flexible SIP trunk pricing solutions that scale as your business grows. See how quickly you can add or remove channels and phone numbers as call volume fluctuates. Elastic SIP trunking is particularly useful because it offers a pay-for-usage model, eliminating significant upfront investments or lengthy provisioning times.
5. Integrations with existing platforms
Verify SIP trunk compatibility with your current tech stack, including your existing UCaaS and CCaaS platforms, and ask about pre-built integrations or APIs for custom setups. Seamless integration streamlines workflows, reduces complexity, and maximizes current investment value.
Streamline, secure, and scale: Your next move with enterprise SIP trunk providers
Enterprise SIP trunking unlocks flexible, scalable global voice capabilities built for the future of business communication. When evaluating providers, focus on network reliability, cost-effectiveness, international coverage, comprehensive security certifications, scalability, and cross-platform compatibility.
AVOXI delivers on all these critical factors and leverages a deep expertise in migration support, helping enterprises transition from on-premises PBX to fully cloud-native infrastructure. With real-time analytics, call recording, automated call routing, and compliance-ready architecture, AVOXI supports mission-critical voice operations across industries and regions.
Want to see the platform in action? Watch the Voice Product Tour for a firsthand look at the features and tools that power enterprise voice at scale. If you're ready to modernize your communications strategy, schedule a free demo to see how AVOXI can support your business.
