The river flows initially to the north and from its junction with its main tributary, the Maichín River, the Trancura turns in a westerly direction until emptying into the Villarrica Lake, after having received the waters of Caburgua Lake through Carrileufú River. This latter river emerges at the Ojos del Caburgua and is fed by the Liucura River, which further has as a tributary the outflow stream of Tinquilco Lake.
The river starts flowing northward, then shifts direction to the west after joining its main tributary, the Maichín River. It empties into Villarrica Lake, with water from Caburgua Lake reaching it through Carrileufú River. This latter river begins at Ojos del Caburgua and is supplied by Liucura River, which has Tinquilco Lake's outflow stream as a tributary.