If you want to change money in Mtwapa the only place that I know of is the Kenya Commercial Bank (KCB). The rates there were not bad actually if you don't fancy a trip into town to change your money.
Barclays do have a smart little ATM though in a room of its own away from prying eyes if you want to get cash with your credit card.
Quite a long way out of Mombasa to the North, this is said to be one of the best hotels on the coast...more
Watamu 10 Mombasa, PO Box 457, Malindi, Kenya
Good for: Families
Malindi Road, Bamburi, 80100, Kenya
Satisfaction: Very Good
Good for: Solo