Following her use on 14 January 1921, UB-86 was dumped on Castle Beach and sold to R. Roskelly & Rodgers on 19 April 1921 for scrap (for £110), and partially salvaged over the following decades, although parts remain in situ.

Like all Type UB III submarines, UB-86 carried 10 torpedoes and was armed with a 8.8 cm (3.46 in) deck gun.

UB-86 would carry a crew of up to 3 officer and 31 men and had a cruising range of 8,180 nautical miles (15,150 km; 9,410 mi).

On 17 August 1918 UB-86 torpedoed the cargo steam ship Denebola 2 nautical miles (3.7 km; 2.3 mi) N by W from Gurnard Head near St Ives, Cornwall.

Denebola, en route from Swansea bound for Rouen, was struck by two torpedoes which hit near number two and three holds causing her to sink rapidly.