Siargao Island ( pronounced shar-gow) would probably be more properly referred to as Siargao Islands, since there are several that make up the area referred to as Siargao, which are governed by the municipalities of the main island. And with an estimated population of well over 200,000 residents on Siargao Island alone, we're not talking an insignificant dot in the Pacific.
It's hard to say how many foreign nationals make the area home. General Luna itself has at least 40 full time foreign residents and probably that many part time, plus varying numbers of tourists from all over the world. Mostly surfers, but the spectrum of interest is very broad, as there is much to do to occupy non-surfers as well.
The locals are friendly, and most speak English to at least some degree. They are very involved in keeping the streets and yards clean, and are very helpful to tourists who may need information about anything Siargao. A welcome and inexpensive change from the more calloused big city environs.
I don't know if it's the diet, genes from the original settlers, or what, but you single guys will be blown away. There are more absolutely beautiful girls on average here than I've ever seen anywhere. Everywhere you look....it's a friggin' enigma...no joke. But act like a decent human being, because much like where I grew up, if you treat family badly someone is going to come looking for you.
Rent a motorcycle and tour the coast, and swing back inland....tons to see and wow you with it's beauty. Magpupungko out Pilar way is an incredible area of tide pools and swimming holes. And the whole coast is an array of unmarked scenic spots, from giant rocks, to jungle shrouded white sand beaches, to mangrove forests with all kinds of critters to check out or fish for.

Island hopping in paradise is another favorite tourist thing you shouldn't pass up. Right across the lagoon from GL we have Guyam and Daku Islands. Great for picnicking, snorkeling, and swimming off their white sand beaches. To the south there is Naked island, so named because it is a bare white sand island, great for swimming, snorkeling, and after a storm unreal shells can be found there. Take some shade though, as there is none to be found on the island.
South/East of Naked you will find the 3 island cluster of Marmon, La Janosa, and Anahawan islands, sitting on the edge of the Philippine Trench. Lefty longboarders will get damp at the sight of up to double overhead lefts with time and room to move at Marmon's north shore, with a hollow right skirting the rocks on the southern. ( A strange phenomenon is the frequency of surf coming in from opposing directions on the same island. Also the odd tides we experience here, with Surigao, a couple hour boat ride away, having tides opposite of those here in GL (General Luna, in Siargao). Not to mention the turbulence and whirlpools seen in the Surigao Strait as the tides race in opposition.)
South/West of Naked island you will find Bucas Grande and it's incredible Sohoton Caves. You really need at least a couple of days to take it all in. Entry is only possible at low tide, as the opening to the large lagoon is itself a cave. Another world in there. Take some good hiking boots, or at least tennies, lights, and picnic type stuff.
See the map of Southern Philippines, and click to enlarge up to virtual map of GL.