Teluk Langsa (Langsa Bay) entered between Ujung Perolin and Tanjung Langsa, about 5 miles SE, is fouled by numerous shoals which are intersected by narrow channels.
The bay is easily identified by the rising ground SWof it against which the island of Pulau Telagatujoh, close NW of Telagatujoh, stands out clearly.

Telaga Tujoh (Telagatujoh), the SE entrance point of the bay, is easy to identify from the E by its sandy beach.

There are three channels of approach into Teluk Langsa, which is otherwise encumbered by numerous shoals, between which there are narrow boat channels, as follows:
1. Alur Pelayaran Birim leads from NE to the mouth of Krueng Birim. The channel is not buoyed. There are depths of 2.7 to 3m in the fairway.
2. Alur Pelayaran Telukdalam, formerly the principal channel to Pelabuhan Kualalangsa, leads close along the W side of Pulau Teleagatujoh. Apart from a fairway approach buoy, the channel is unmarked. There are least depths of 2.4m on the outer and inner bars.
3. Kuala Langsa, the principal channel, leads on the SE side of Pulau Telagatujoh through Krueng Langsa to Pelabuhan Kualalangsa.
This channel is marked by buoys and lighted range beacons.
There is a reported least depth of 1.5m close SE of range line. Vessels up to 100 dwt can reach Kualalangsa.
The tidal currents run with considerable strength in the mouths of the various rivers and generally set in the direction of the channels. The strength of the currents is sometimes felt well outside the 10m curve.