Mnemba Atoll — Zanzibar

Every dive is a boat dive, and the day starts on the sand: tanks are carried out to a boat pulled up on the beach at Matemwe or Nungwi and pushed off through the shallows. From Matemwe the crossing takes minutes, from Nungwi or Kendwa closer to an hour, which shapes how much of the morning is spent travelling. Centres generally run a two-tank morning, come back for lunch, and offer a single afternoon dive on the inshore reefs. Snorkelling boats converge on the atoll by mid-morning, so the early departure is worth taking.

The reef is a ring around a low private island, and which part of it gets dived is decided by wind rather than preference. The north-east monsoon is the lighter of the two, so through the turn of the year the boats can usually reach the exposed northern and eastern faces; once the south-easterly kusi picks up mid-year, those sides turn lumpy and everything shifts into the western lee. Between the coral are sand channels and rubble patches worth slowing down over, and the reef top is shallow enough that safety stops are spent over live coral rather than hanging in blue.

The atoll is small, so a week of diving means repeating sites. Most people accept that, because the shallow reef is undemanding and there is usually something moving over it. Divers who want a harder dive add Leven Bank, the submerged bank off Zanzibar's northern tip usually run out of Nungwi, where the current is real and the fish are bigger, though it only goes when conditions allow. The Mnemba programme has no wrecks in it and nothing that counts as shore diving.

That makes it a straightforward first destination: courses fit around days spent elsewhere on the island, non-diving partners see the same reef with a mask and snorkel, and the logistics ask nothing of anyone. Experienced divers tend to find it pleasant rather than testing and pair it with a few days on Pemba or further down the Tanzanian coast. Stone Town and the spice farms inland are close enough to fill a surface interval of a day or two.