Marks the South entrance of Achill sound. The fishing harbour at Cloghmore (at the very south tip of Achill) offers good shelter in all weather, but the bar East of Achill beg may break especially on the ebb. In bad westerly weather with swell the south entrance of Achill sound is safe only at the end of the flood. The area South of Achill beg can also get quite rough with a Westerly swell running against the tide, although it is still better than on the South side of Clare Island if you must get into Clew bay in a Westerly gale. In reasonable weather with no swell, Cloghmore can be entered at all time as it it is well lit (leading lights) and there's enough water over the bar for a yacht, even at LWS.
Tide in the channel between Achill and Corraun turns about 1 hour after HW in Westport and runs at over 4 knots.
There's a lovely anchorage off the beach East of Achill beg.
The Achill beg light also signals the North entrance to Clew bay, where the small drying harbours of Westport and Newport offer opportunities for shopping. There are a number of excellent anchorages in the bay.
The southern entrance to Clew bay, South of Clare Island, is not well lit, and shouldn't be attempted at night unless one is sure of their position.