Construction of the lighthouse began in 1887, led by
Sir James Douglass, Engineer in Chief of
Trinity House. A light was lit on a temporary structure in February 1889 and the lighthouse itself began operating on 3 September 1890. The light was initially powered by a six-wick
Argand oil burner; it displayed a
group occulting characteristic (the light being eclipsed twice every 20 seconds) and had a visible range of . The light was white, but shone red across defined
sectors to the north and to the south (indicating the Barnard sands and Sizewell Bank respectively); in addition, 'spare' light, which would otherwise have shone needlessly westwards, was diverted by way of vertical
condensing prisms so as to intensify these red sectors. The inexperience of the new lighthouse keepers was blamed for the fire. Both lighthouses were reprieved in 2009 following a review by Trinity House that found that satellite navigation systems were not yet sufficiently reliable. Then in December 2012, the range of Southwold's light was increased to , to compensate for the imminent closure of
Orfordness Lighthouse (which took place in June 2013). This was achieved by installing a new main light: a BLV Topspot 90 Volt Metal Halide 150-watt lamp placed within a small revolving optic. The central and lower sections of the old lens, together with its lamp, have been retained for use as an emergency backup. == Current display ==