Padre Island Rentals, Fine Homes & Condominiums from pirentals.com. South Padre Island Texas is part of the world`s longest barrier reef island located at the southernmost tip of Texas Gulf Coast. It is separated from the mainland by Laguna Madre and connected by the Queen Isabella Causeway at the south end. With its warm tropical breezes and compact size the city of South Padre Island comes alive with thousands of island vacationers each year getting intimate in search of sand, sun, and fun.