The Sixaola River (Spanish: Río Sixaola) is a river in southern Limón Province, Costa Rica. It flows from the Cordillera Talamanca to the Caribbean Sea northeast of Sixaola at (9°34′20″N82°33′54″W). The river's headwaters are part of the La Amistad International Park. For part of its length, the river forms the border between Limón Province, Costa Rica and Bocas del Toro Province, Panama. An old railroad bridge spans the river between Guabito, Panama and Sixaola, Costa Rica. This bridge is a border crossing between Costa Rica and Panama.