Phu Quoc: fine in town, thin at the edges of the island

Where the signal is, and where it is not

Phu Quoc is Vietnam's largest island and the furthest of its major destinations from the mainland. That shows up in the coverage rather than in the price — you pay the same as anyone else in Vietnam, you just get less reach at the edges.

Duong Dong, the island's town, and the main resort strip along Long Beach and Sao Beach are fine. The gaps sit around them. The national park interior, which takes up much of the centre and north of the island, is limited. The far northern beaches — Bãi Thơm and Gành Dầu — are variable. And the boat trips south to the An Thoi archipelago, including Hòn Thơm at the far end of the cable car, have limited signal between the islands.

For most visitors that adds up to nothing at all. You are on a beach or on a boat, and neither needs a phone. It starts to matter if you are riding north expecting maps to keep working, or if a dive boat needs to reach you.

The Viettel advice you cannot actually follow

The standard line on Phu Quoc is that Viettel has the best reach on the island and you should make sure your eSIM uses it. The first half is the general reputation of the network. The second half is not something you can carry out.

Airalo does not publish a host network for Vietnam, and neither does Saily — its pages, read on 16 August 2026, promise a connection from Vietnam's best networks and name none of them. Nomad publishes none either, in Vietnam or anywhere else it sells — an earlier version of this page said its listing named Mobifone and Vinaphone, and that was wrong. Holafly publishes nothing either; the GPC Vinaphone entry our data carried against it was ours rather than the seller's. One provider publishes something, and only as its own claim: eSIMCard's listing names Mobifone. Nobody has confirmed it against the carriers, and it is not Viettel, so nothing on sale gives you the network you would want when you ride out to Gành Dầu.

So if that reach genuinely matters to your trip, the reliable route is a physical Viettel SIM rather than a plan you hope is on Viettel. Vietnam requires a passport to register a prepaid SIM, so it is a counter transaction rather than something you grab off a shelf. Phu Quoc's airport is small — do it before you leave the terminal, because the shops in Duong Dong are a taxi ride away. Our figure for a Vietnamese airport SIM is about $7.

What a week here actually costs

From our Vietnam plan data — Airalo checked 13 August 2026, Saily 16 August:

A beach week is light. Bookings, maps, a ferry timetable and photographs fit inside 3 to 5 GB for most people, and the offline days are genuinely offline, which keeps the number down further. Saily's 3 GB month at $7.99 is the best-shaped plan for that, undercutting Airalo's 3 GB week by a cent and lasting four times as long.

The interesting arithmetic is further up the ladder, and Vietnam's does not stop at 20 GB. Airalo's verified 50 GB month at $49 works out at $0.98 a gigabyte, and Nomad's verified 50 GB at $39 at $0.78, against $2.20 for the verified 5 GB month at $11. That is a real gap — but it is only worth crossing if Phu Quoc is one stop on a longer Vietnamese trip. For an island week on its own, buying 50 GB to save on the rate is spending $38 to avoid $11.

Before you get on the boat

• Download offline maps for the whole island, not just the resort strip
• Confirm dive and island-hopping bookings the night before, from your hotel
• Save the operator's number somewhere you can read without a connection
• Expect the An Thoi crossing to be dead, and treat it as part of the day

Full provider-by-provider pricing is on the Vietnam hub.