Da Nang city and My Khe beach are straightforward on Viettel. The Hai Van pass and the tunnels on the way north are where the signal drops, then returns when the road drops back to the coast.
Beach, river, airport
Da Nang is a low city between the sea and a mountain wall. The airport, the Han River hotels, and My Khe are all inside one urban coverage area. You can land, turn the Vietnam line on, and be at the beach while the phone is still the thing you navigate with. Indoor concrete hotels facing away from the street are the boring failure. Balconies facing the sea are usually fine.
The pass
Hai Van is the first place on a central-coast trip where “Vietnam has good 4G” stops being a blanket sentence. The tunnel is a tunnel. The old pass above it has curves with a view and a weak or missing cell, then a strong cell again on the Hue side. Viettel’s rural grid is why this road is usable at all compared with a thin roaming partner. It does not fill in every switchback. Save offline maps the night before. A navigation app that must download the next tile at the mouth of the tunnel will spin.
South of the city, the road to Hoi An is flat and ordinarily covered. The ancient town itself is discussed on the Hoi An page: pedestrian streets, thick old houses, and a perfectly good signal on the river road. You do not swap eSIMs between the two towns. One profile, one daily 5GB, reset at 23:59 Vietnam time.
A beach day with music and chat is comfortable inside 5GB. Uploading a drone card or hotspotting two extra phones is how you finish the bucket before dinner. When it is finished, both the phone and the hotspot stop. There is no slow fallback. If you still need data that evening, the current product cannot be topped up in place. Another plan is a separate QR.
Get the local Viettel eSIM
7 days $9.99, 15 days $14.99, 30 days $18.99. 5GB high-speed per day. Use code HelloVietnam for 10% off.
Sometimes, not as a promise. Treat 4G as the working assumption. The national 5G coverage score for Viettel was low in the August 2026 Opensignal report.
Will navigation work on Hai Van?
Download the offline map. Live traffic will pause in tunnels and on the exposed side of the pass. The route itself should be saved before you start.
Is Hoi An the same eSIM?
Yes. It is the same Viettel profile, about an hour south depending on traffic.
What uses the most data here?
Hotspot on a laptop, cloud photo backup, and video. Maps and Grab do not.
Who measured the speeds?
Not us. Opensignal, nPerf, and Ookla, cited under the figures. None of those sources gave us a Da Nang-only table.
