A variety of scuba operators have offices around the Semporna seafront complex and/or in KK.
The vast majority of travellers come to Semporna to dive or snorkel, either jetting off to Pulau Mabul and the other islands, or staying in town and diving in the Tun Sakaran Marine Park. Scuba is the town's lifeline, and there's no shortage of places to sign up for it. If you have your heart set on diving at Sipadan, book up to three months in advance in peak season (July and August) and several weeks in advance the rest of the year. Only 120 permits are issued daily, and not all diving operators go to Sipadan.