The nearest airports are at Surat Thani and Phuket. Depending on location of stay or departure location of boats, both airports are in 70-100 km range. A third airport is situated in Krabi, around 150 km away. There are regular bus/minivan/taxi services to Khao Lak from the airports.
There are some liveaboard boat services operating from the mainland, from the nearby Khao Lak to as far as Phuket and Ko Lanta. Many of companies advertising trips to Surin Islands are misleadingly operates to Koh Ban and Koh Tachai only. These islands are 50km south and belongs to Similan Islands. Due to commercial reasons various websites mentions both of these Islands as part of Surin Islands, they are not.
Bokings for liveaboard services can be arranged from some hotels or guesthouses, if not, there are always smaller agencies around the corner everywhere. Another alternative is doing daytrips with boat services from Khao Lak which is 90 km from the islands.