The best currency to have with you in Seychelles is euro. Taxis, accomodation, day trips are paid in euro. Local currency is used to pay in restaurants, local shops or entrance fees for different attractions. If you are from UK or USA you can bring with you GBP or USD and you can change it at Nouvobanq, MCB, Barcalys or Cash Plus. ATMs are widely spread so if you don't want to carry cash with you don't worry you will withdraw local currency at local ATMs.