Diving in Nha Trang: Hon Mun shut in 2022, so where do you dive?
Swimming and diving around Hon Mun stopped on 27 June 2022 and had not reopened by July 2026 — yet tours still sell the reef. Where the four permitted areas are, and the one question that replaces all the others.
This piece has no expiry date, but it was written on the date above. Prices, opening hours and street names may have moved on; ring ahead about anything that matters.
Reference photo
Search for “diving at Hòn Mun” and you get dozens of programmes, at every price, updated for 2026, illustrated with bright coral. What almost none of them mention: the Nha Trang Bay management board halted “swimming and diving at every dive point around Hòn Mun island” on 27 June 2022, and as of July 2026 nothing had reopened it.
The scope is wider than people assume. The original notice covered swimming and diving at every dive point around the island. By the bay-restoration progress report of July 2024, the board itself had added boats and glass-bottom coracles to what was suspended at Hòn Mun, and a news report in July 2026 still described the strictly protected zone as closed to swimming and diving. This is not a rule someone forgot; it keeps being restated.
The reason is the coral, and it is specific. Typhoon No. 9 in December 2021 tore up the western and north-western reef, and a bleaching event followed. Reef-building hard coral grows about a centimetre a year, so damage like that does not come back inside one tourist season. The closure has worked, measurably: surveys in late 2022 and March 2023 put live coral cover on the north and south-west of the island at about 74.5%, inside the good band, which is also why nobody is rushing to lift it.
So where can you dive. In June 2024 Khánh Hoà approved a trial of recreational diving at four areas in the bay, and Hòn Mun is not among them: north of Hòn Rùa island; the artificial reef laid off Vĩnh Hoà; north-east of Trí Nguyên island; and the water between Bãi Tranh and Bãi Sỏi, east of Trí Nguyên. The trial runs one year from the date operators are licensed, after which the province reviews it — so this is a list with an expiry date, not a fixed rule.
So when booking, the question worth asking is where exactly guests get into the water, rather than whether the boat calls at Hòn Mun. Boats passing through that water are not covered by the suspension, so the island's name in an itinerary means nothing; what you need is the entry point. A seller who can answer with one of the four names above is fine. One who only repeats “Hòn Mun”, or says it will be decided out on the bay, has also answered.
Snorkel or tank matters less than any of that. Snorkelling is a mask, a snorkel and a buoyancy vest at the surface; no swimming ability, no certificate, and usually already inside the island-tour price. A guided scuba dive — the try-dive — takes you down a few metres with an instructor one-to-one or one-to-two, charged separately, and also needs no certificate.
The real difference is not depth but that snorkelling only pays off where the reef is shallow — and the bay's best shallow reef is the closed one. So at the four substitute areas, whether a snorkel is enough has to be asked site by site.
One more thing is happening right now. In July 2026 the bay board warned of bleaching risk and set up a temporary protection zone at Hòn Chồng – Đặng Tất from May to August 2026, with access restricted between 16:00 and 18:00 on low-tide days. The threshold it cites is sea temperature above 30.5°C sustained for two to three weeks. If you are here in the hot months and find a stretch of water roped off, that is what it is: go around it, don't swim through.
Two things I could not settle, said out loud rather than hidden. The four-area trial was approved in June 2024 for one year from licensing, and I could not find the licensing dates for individual operators, so I cannot say whether it still stands today or has already been reassessed. Nor do I know whether tour boats still stop in the water around Hòn Mun, since the order covers activity in the water rather than passing traffic.
Sources: the Nha Trang Bay management board's suspension of swimming and diving around Hòn Mun, effective 27 June 2022; the four-area diving trial agreed by the Khánh Hoà provincial People's Committee in June 2024; the July 2024 progress report on the master plan to restore Nha Trang Bay by 2030; and the July 2026 coral-bleaching warning for the bay. The related pages on this site are below.
