What it is
An archipelago of about thirty islands off Cabo Delgado, running from Ibo, a Swahili and Portuguese trading island of coral-rag houses and a star-shaped fort, north to Medjumbe and Vamizi. Mangroves, deep channels and reef in good condition.
Why go
On paper it is the best combination on this coast: the least-visited reef in the region, and in Ibo a genuine historic town rather than a resort. Diving here is quiet in a way the southern sites are not.
When to go
The dry months, June to October, for the sea and the island crossings. But the season is the second question, not the first. Cabo Delgado has had an armed insurgency since 2017, and several governments advise against all or all-but-essential travel to parts of the province. Check your own government's advice for the specific district on the day you book and again before you fly, confirm that your insurance covers you there, and be prepared to change plans. This is not a place to take a chance on, and it is not a first trip to Africa.
Most people stay 4-5 nights.