If you're going to stay in the Oslob area longer than your 21 day visa ,you'll have to apply for a 59 day extension and the closet Immigration office is in Dumaguete. Here is a idea of what it's like to cross the harbor at Santander and a quick glance at the Immigration office and some of the businesses near it. Attention: There is now a  ATM machine in the Oslob marketplace that will only accept Philippino cards. Otherwise,if you need to use an international card,Dumaguette is the closest location. There are terminals in: Robinson Mall, Lee Mall, BPI bank.