The main tower is built of tarred and white-painted granite ashlar with a cast-iron lantern roofed in copper.

[4] The original main optic consisted of a rotating octagonal array of eight large (first-order) Fresnel lenses, topped by seven tiers of concave mirrors.

At the time its six lens panels (at 60° to the circle) were 'the widest in azimuth hitherto constructed, except some of those of Flamborough Head';[10] the increase in power, compared to the old 45° lenses, was of the order of 3 to 2.

[8] At the same time the main optic was replaced by a smaller (third-order) catadioptric lens, made up of two groups of three asymmetrical panels, which produced a group-flashing light characteristic.

[11] Work began on the automation of Start Point Lighthouse in August 1992 and was carried out by LEC Marine at a cost of £82,754.

In 2018 the rotating optic (which had been in use since 1959) was replaced by a two-tier LED lantern;[12] the old lens was put on display in the adjacent visitor centre.

[13] The light alone was found to be inadequate in fog, and a bell was installed in 1862; the machinery was housed in a small building which still stands on the cliff face to the south-east of the lighthouse.

The fog siren was housed in a circular building, just to the south of the lighthouse, and sounded (one blast every three minutes)[15] through a roof-mounted horizontal horn which could be turned in the direction of the prevailing wind.