A short boat ride from Iboih Beach, Rubiah Island is the centrepiece of snorkelling and diving around Sabang. The shallow reefs on the island's southern side are accessible to snorkellers directly from the water — no boat required if conditions allow — while the deeper sites on the outer reef walls attract experienced divers. Reef sharks patrol the outer edges, and the coral gardens are dense with parrotfish, angelfish, and lionfish.
The island itself is small and uninhabited, ringed by mangroves on one side and coral-fringed sand on the other. You can walk across it in ten minutes. Day-trippers from Sabang town usually combine Rubiah with a stop at Iboih beach; the crossing is included in most dive packages from operators based at Iboih.