Internet on a Yacht: Connected Well Beyond the Coast

Anyone planning internet for a sailing yacht almost always asks the same question: does it still work 25 NM off the coast? The honest answer depends on the type of connection. Mobile networks and satellite behave fundamentally differently here.

A smartphone alone typically still picks up a usable network at sea up to roughly 10 to 15 NM off the coast, according to the trade press. The reason is physics: range is limited by the radio horizon, which depends on antenna height, not transmit power. An external marine antenna, mounted high and clear on the mast, reaches significantly further, according to manufacturers. Digital Yacht cites up to 25 NM; yacht.de and boote-magazin.de cite manufacturer figures of up to 30 NM, depending on network coverage, weather and antenna height.

The frequency band matters too: low bands such as LTE Band 20 (800 MHz) or 5G n28 (700 MHz) carry far, while the newer 5G high bands around 3.4 to 3.6 GHz are short-range. Simrad points out that effective range has tended to get shorter with each mobile generation. Cable loss adds to this: a long antenna cable eats into gain. That's why we mount antennas no higher than spreader height at most, or use a dome with an integrated modem on the mast, connected by a single Ethernet cable (Peplink: "minimal cable loss"). The antenna also shouldn't sit level with VHF or AIS antennas, as the devices can otherwise interfere with each other.

For the original request, that means: 25 NM is roughly the limit of what mobile networks with a mast antenna can still deliver, network-dependent. In this zone, only satellite is reliable. The consequence: Starlink takes over offshore and on passage, mobile networks near the coast and in port, both bundled with automatic switching.

A reliable 5G router for the boat is a small system, from the dome on the mast to the cabin. At its centre is a dome with an integrated 5G modem and antennas, mounted on the mast or an equipment carrier, as high and clear as possible. A single Ethernet cable with Power over Ethernet runs from the dome to the router below deck; a separate power supply is not needed. The Starlink antenna is also connected via Ethernet.

The router handles the bundling: via Peplink SpeedFusion it connects to a hub in the Ascend data centre and combines Starlink with mobile networks using Hot Failover. In our live test with Starlink, three mobile networks and a Peplink SDX Pro, the connection stayed up without interruption when one line was disconnected. A Peplink AP One AX over PoE provides Wi-Fi in the cabins and saloon. In port, the marina Wi-Fi can be connected as a Wi-Fi WAN, provided the signal is stable enough.

For the zones where mobile networks reach, we recommend the Ascend data plan as a multi-network SIM. In Germany, one SIM automatically registers with Vodafone, O2 or Telekom (multi-IMSI), either by best network or a fixed network choice. The plan applies EU-wide at the same price, is prepaid and stops at €0. Usage is updated every 30 minutes. The SIM is available as a triple-cut SIM or eSIM, cancellable monthly, with an internet gateway in Frankfurt and a German IP address. For yachts, this is the simplest solution: one SIM for the North Sea and Baltic Sea, the Atlantic coast and the Mediterranean within the EU, with no contract commitment and no manual network switching. We supply the SIM together with the router, pre-configured and ready to use, with APN and network selection set up. You'll find the right router on our routers for SIM cards page; just ask us for the SIM at the same time: request a SIM card.

Peplink documents several installations in its "Luxury Super Yachts" case study. On board M/Y Albatross (Europe, Mediterranean, Caribbean), 2× MAX BR1 LTE units with redundant SIM slots provide automatic provider switching, according to Peplink. 7× AP One AC mini units deliver Wi-Fi throughout the vessel. On M/Y Limitless, an HD4 bundles connections via encrypted SpeedFusion; on M/Y Veloce, a MAX HD2 with AP One supports VoIP, Sonos and Apple TV, among other things.

These models are no longer current. Their successors: MAX BR1 became the MAX BR1 Pro 5G; MAX HD2/HD2 Dome became the HD1 Dome Pro and Dome Pro Duo. HD4 became the MBX series, and AP One AC mini/Enterprise became the AP One AX. We implement the same principle today with current hardware.