With untouched corals and a wealth of marine life (including lionfish, scorpionfish, moray eels and large schools of fusiliers), snorkelling the shallow reefs around the Southwest Gilis is a highlight of any trip to Lombok.
The northwestern coast of Gili Gede provides the best shore snorkelling for those sleeping on the island, but you'll probably want to hire a boatman to take you to the southeastern coasts of Gili Layar and Gili Rengit, both of which have extremely healthy coral and massive schools of fish. You can also tack on tiny Gili Goleng, where seahorses amble around in the offshore seagrass. The entire trip should cost around 500,000Rp for the boat and gear.
Closer to Lembar are the smaller islands of the Gita Nada group (Gili Nanggu, Gili Kedis, Gili Tangkong and Gili Sudak), all of which are fantastic for snorkelling. Boatmen can take you here from Gili Gede for about 600,000Rp, or you can visit on a day trip from Kuta with Scuba Froggy or Mimpi Manis.