Gili Air is the closest to Lombok of the three Gili islands. In size, it lies between Meno and Trawangan, and has the largest "normal" community.
Unlike Gili Meno and Gili Trawangan, Gili Air actually does have its own water source and you'll notice immediately how much greener and overgrown it is compared to the other two far more arid islands. Much of the interior is given over to coconut cultivation, though tourists are proving themselves a more lucrative crop and slowly the palm plantations are either making way for places to stay or at least shading bungalows beneath.
The island is ringed by a very pretty beach with some quite respectable snorkelling offshore. We didn't have time to snorkel the entire island, but off the southwest coast there are some good intricate banks of coral, while the west coast (high tide only) can be a good spot for spotting turtles. We didn't snorkel the east coast, but we saw lots of others who did, so there must be something out there! All around the island there is evidence of beach being swept away, and again the west coast tended to be the less affected.
Bicycles are easily hired and there is a quite good (albeit confusing) network of sealed paths around and throughout the island, making it far easier to explore than Gili Meno.
As with the other islands, the majority of the population here is Muslim and there is a large mosque towards the south-central part of the island. Unlike on Gili Trawangan, there are few guesthouses close by so you're unlikely to hear the call to prayer.
Most of the accommodation is clustered at the southwest and west coast of the island, though there is a smattering of places the entire way around it. The northeast (sunset) area is the most isolated -- and in our opinion -- the best.