OpenVPN: Reliable Compatibility Across Devices and Networks
OpenVPN remains the most widely supported VPN protocol. It works on almost every operating system and router, and many travel-focused VPN services offer it as a default. The protocol uses the OpenSSL library for encryption and runs over TCP or UDP. On TCP, OpenVPN can sometimes pass through firewalls or corporate guest networks that block UDP traffic, making it a fallback option in restrictive environments like hotel Wi‑Fi or airport lounges.
However, OpenVPN is not the fastest choice. The single-threaded encryption process uses more processor power, which can drain battery noticeably on a phone or laptop. On networks with packet loss, the TCP mode can also compound delays. For a traveller who needs reliable access on a public network and is willing to trade some speed for compatibility, OpenVPN is a safe default. Many travel eSIM users keep OpenVPN as a backup profile even if they normally use a lighter protocol.
When you switch between mobile data and Wi‑Fi, OpenVPN may drop the connection and require a manual reconnect. This matters if you walk through a train station or move between hotel floors. If you expect frequent network changes, consider a protocol designed for seamless transitions.
WireGuard: Faster Speeds and Lower Battery Drain on Modern Devices
WireGuard is a newer protocol that uses modern cryptography and a simpler codebase. It runs over UDP only and aims to establish connections in milliseconds. For travellers, the main advantages are speed and efficiency. WireGuard typically delivers higher throughput than OpenVPN on the same server, and it uses far less CPU time, which keeps your phone cooler and extends battery life during long flights or layovers.
Because WireGuard is stateless, it handles network changes better than older protocols. If you move from Wi‑Fi to mobile data, the tunnel can resume without a full renegotiation. This makes it a strong choice for travellers who move between networks throughout the day. However, some restrictive networks block all UDP traffic or explicitly filter WireGuard's handshake. In those cases, the protocol may fail silently and you may need to switch to OpenVPN over TCP.
WireGuard is available on iOS, Android, Windows, macOS and Linux. Many VPN providers now offer it as an option alongside OpenVPN. For a Singapore traveller whose device supports it, WireGuard is often the best everyday protocol. Just keep a fallback profile ready for networks that block UDP.
IKEv2: Smooth Network Switching for Mobile Data and Wi‑Fi Roaming
IKEv2 (Internet Key Exchange version 2) is a protocol that handles network transitions gracefully. It was designed to keep a VPN tunnel alive when you switch from one internet connection to another, such as moving from a hotel Wi‑Fi to a mobile hotspot. For travellers who rely on a portable eSIM device or move between data sources frequently, IKEv2 can maintain the connection without requiring a manual reconnect or app restart.
IKEv2 also supports the Mobility and Multihoming (MOBIKE) standard, which allows the tunnel to survive IP address changes. This is useful when you take a taxi or MRT ride and your phone switches between cellular towers. The protocol is natively supported on iOS and macOS, and most modern Android and Windows devices support it as well. It uses IPsec for encryption, which is considered secure when properly configured.
One limitation: IKEv2 may not work on networks that block IPsec traffic or that use strict NAT (network address translation) configurations. Some public Wi‑Fi portals interfere with IKEv2 negotiation. In those cases, you may need to fall back to OpenVPN. For a traveller who values connection stability over raw speed, IKEv2 is a practical choice, especially if you spend time on trains, buses or in areas with patchy coverage.
Older Protocols: PPTP, L2TP and When to Avoid Them
PPTP (Point-to-Point Tunnelling Protocol) and L2TP (Layer 2 Tunnelling Protocol) are older protocols that still appear on some devices and VPN configuration menus. PPTP is fast and simple, but it uses weak encryption that has known vulnerabilities. No reputable VPN service recommends it for protecting travel data. L2TP, often combined with IPsec, offers better encryption but can be slower and more prone to connection drops on high-latency links.
For a traveller in 2026, these protocols are rarely the best choice. They can be useful only if your device or network blocks every other option, for example, on a very old router or an enterprise network that whitelists only L2TP. Even then, you should treat any data sent through these tunnels as potentially visible to third parties. Avoid using PPTP for any activity that involves login credentials or personal information.
If your VPN provider still lists PPTP or L2TP as available protocols, consider whether newer options like OpenVPN, WireGuard or IKEv2 are also offered. Most modern travel eSIM users will never need to enable an older protocol. Stick with the supported, audited options and keep your VPN app updated so that your protocol choices remain secure.
