Many customers have reported issues using 2ndNumber in the Caribbean islands. Sadly, this is mostly a result of the restrictions in place by the local providers of internet connections. This article goes into some technical details for those interested.
Despite there being no official blanket ban or policy in most Caribbean countries against VoIP, many ISPs in the region do engage in some level of VoIP filtering, blocking, or throttling — especially for services that compete with their own telecom offerings.
Here’s what’s likely going on:
1. ISPs Protecting Their Own Revenue
Many Caribbean ISPs also operate mobile and landline networks. VoIP services (like SIP or WhatsApp calling) directly compete with their expensive international calling rates. As a result, they have a strong incentive to degrade or block these services, especially during peak hours or for specific ports/protocols.
2. Unacknowledged or Silent Filtering
There are reports (and plenty of anecdotal evidence) of:
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SIP traffic being blocked or heavily throttled
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UDP ports (like 5060, 5061) being silently filtered
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Packet inspection targeting VoIP signatures
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VPNs being required just to use softphones
But this is often done quietly, without notice or policy transparency — especially in smaller islands.
3. Different Rules by ISP or Island
Some islands or even individual ISPs are worse than others. For example:
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Haiti, Jamaica, and the Bahamas have had repeated user reports of VoIP issues.
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Digicel has been accused in the past of blocking VoIP and charging extra for "unlocked" internet.
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Flow has had similar complaints, though it varies by country.
4. It’s Not Always Malicious — Sometimes It's Bad Routing
In some cases, it’s not deliberate blocking, but:
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Carrier-grade NAT issues
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Poor international routing
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Firewall misconfigurations
Still, if it’s only happening in the Caribbean and consistently so, filtering is the most likely cause
What You Can Do
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Use a VPN (2ndNumber has it's own VPN.) – this often solves the problem.
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Use WebRTC-based softphones – they are harder to detect/block - our WebPhone is a WebRTC softphone.
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Switch to different SIP ports (e.g. 5062, 5160, etc.) or use TCP instead of UDP.
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Report the issue to pressure ISPs (though success is limited).
In summary: even if unofficially, VoIP filtering absolutely does happen in the Caribbean. The tech and behaviour from ISPs point clearly in that direction, even if they don’t admit it.
