Mafia Island, south of Zanzibar, is one of the best places in the world to swim with whale sharks. From about October to March, these gentle giants gather in the bay off Kilindoni to feed on plankton, often close to the surface and close to shore.
About whale sharks
The whale shark is the largest fish in the world. Most seen off Mafia are young males between 4 and 9 metres long. They feed by filtering plankton and are harmless to people. Many return to Mafia year after year, and researchers have identified individual sharks by the spot patterns on their skin.
When to go
| Months | Whale sharks |
|---|---|
| October–November | Season starting, numbers building |
| December–February | Peak, with the most reliable sightings |
| March | Season ending |
| April–September | Rarely seen |
How the trips work
Boats leave Kilindoni in the morning with a spotter. When a shark is found, small groups slip into the water with a mask and snorkel and swim alongside it. No diving experience is needed, but you should be a confident swimmer. Trips usually take three to four hours.
Swimming responsibly
- Keep at least 3 metres from the shark’s body and 4 metres from its tail.
- Never touch, chase or block a shark.
- No flash photography.
- A small number of swimmers per shark at a time.
- Boats keep their engines off or idle near the sharks.
More to do on Mafia
- Diving and snorkelling in Mafia Island Marine Park, with healthy coral, turtles and reef fish.
- Turtle nesting on Juani Island between roughly June and September.
- Chole Island, with ruins from the 19th century and fruit bats.
- Sandbank picnics at low tide.
Getting there
Light aircraft fly to Mafia from Dar es Salaam in about 30 minutes, and from Zanzibar. See Mafia whale sharks and read which Tanzanian island to choose.
Frequently asked questions
From about October to March, with the best sightings from December to February.
No. They feed on plankton and are harmless to people. Keep your distance and never touch them.
No. Sightings are by snorkelling at the surface. You should be a confident swimmer.
