Cerrig-yr-Adar is the address of Outdoor Alternative, a campground and group accommodation site located in Rhoscolyn on the Isle of Anglesey (Ynys Môn), North Wales.

Operating since 1985, the facility sits on seven acres in a corner of Ynys Gybi and caters to families, friends, schools, universities, and outdoor groups, offering year-round accommodation for parties of 8 to 45 people.

The site benefits from Anglesey's notably high sunshine hours — among the highest in the UK — and the operators have made sustainability a priority, including solar power generation and efforts to naturalise meadows to support pollinators and local wildlife.