The local currency is the Malaysian Ringgit (RM or MYR).
In general, transport, food and accommodation in Sabah is expensive compared to other South East Asia countries.
On the other side, PADI diving courses here are among the cheapest in the world.
Where to get money in Semporna
Foreign currencies and travelers' cheques and can be changed for Malaysian Ringgit at Semporna's MayBank.
The local MayBank ATM will allow you to withdraw 5000 RM (1500RM for each transaction) max per day (accepts Visa, Mastercards, Maestro, etc).
There are also a money changer kiosks available in Tawau airport.
Free Online Currency Converter: xe.com
Monday through Friday from 9.30am to 3pm
Exchange rates (valid only at the time of writing).
100 RM = 24 USD
100 RM = 22 EURO
100 RM = 19 GBP