Where they are
The Amboni caves are a limestone system in the coral limestone north of Tanga city, at Kiomoni on the road towards the Kenyan border, a short drive from the centre. They are the best-known cave excursion on the Tanzanian coast and the reason most visitors to Tanga allow a morning rather than an hour.
They are also a working place of worship. Ritual use of the caves by local communities is long-standing and continues, which shapes how a visit is conducted and what you should and should not photograph. That is the single most important thing to arrive knowing.
The state of the record
Something odd sits behind almost every description of Amboni you will read, and it is worth setting out.
Tanga City Council publishes no tourism or heritage material at all. The one page on a Tanzanian government domain that describes the caves at any length belongs to the Ngorongoro Conservation Area Authority — a body six hundred kilometres away with no responsibility for Tanga — and that page carries copied third-party material, which is visible in its own question-and-answer section, where the answers are about the Ngorongoro crater and direct readers to a different website entirely.
So the caves are real, well known and easy to visit, and the numbers attached to them have no custodian. Figures for their extent range from a few hundred metres of accessible passage to claims of hundreds of square kilometres and tunnels running to Kenya. Ages from the Jurassic onwards are asserted. None of it can be traced to a survey. None of it is repeated as fact here.
What a visit is actually like
Practically, a guided visit takes you through one section of one chamber system by lamp. The passages are humid, the floor is uneven and slick in places, and bats are present in numbers. It is caving in the loosest sense — walking, stooping and some scrambling rather than anything technical — and it does not require equipment beyond shoes you do not mind ruining.
The cave exploration guide sets out what caving in Tanzania involves generally, including the question of lighting and what to do about the near-total absence of published safety information at sites like this one.
Amboni combines naturally with the other short trips out of Tanga — the ruins south of the city and the bay — and the historical walking tours guide covers the city itself.
Common questions
How big are the Amboni caves?
Not established. Published figures vary by orders of magnitude and none can be traced to a survey. The one Tanzanian government page describing the caves belongs to an authority with no connection to Tanga and carries copied third-party text.
Are the caves still used for worship?
Yes. Ritual and religious use by local communities is long-standing and continues alongside visitor access, which is worth respecting in how you behave and what you photograph.
Do you need caving experience?
No. The visited section is walked with a guide and a lamp. It is wet, uneven and dark, which is a matter of footwear and care rather than skill.