IRA operations have centred on bombings and shootings aimed at the security forces and British troops in Northern Ireland, and have included attacks on civilian targets, such as shopping centres, railway stations, and motorway bridges, and specific assassination targets, such as Members of Parliament. The most notable of these assassinations was that of Louis Mountbatten, who was killed along with three others when his boat was blown up by an IRA bomb at Mullaghmore, Country Sligo, Republic of Ireland, on August 27, 1979.

Although many of the bombs used have been small enough to be planted manually, the car bomb became a preferred weapon in the 1970s, reaching a peak of destruction in July 1974 when more than 20 car bombs exploded in one day in Belfast. From 1974 the bombing campaign was extended to mainland Britain and included a series of attacks in pubs, railway stations, shops (such as Harrods in London), and shopping centres. Coded warnings to newspapers and other organisations were sometimes used.

Massive economic disruption was wrought in 1992 and 1993, when several vast lorry bombs were detonated in London. One of these destroyed the Baltic Exchange in the City of London on April 10, 1992, killing three people. The IRA is regarded as the world's most experienced bombing organisation; it has used bombs ranging from small handheld incendiary devices to lorry bombs weighing hundreds of pounds, such as the 230 kg (500 lb) bomb exploded at Canary Wharf.

Nitrobenzene and fertiliser are used in large bombs designed to blow up buildings or in smaller devices designed to be thrown at the Northern Ireland security forces. Home-made weapons have included the nail bomb and the "drogue" bomb, an anti-vehicle grenade consisting of about 230 g (506 lb) of explosive packed into a tin attached to a throwing handle.

Home-made explosives are made of fertiliser and diesel-oil mix. The largest of these weapons was the vast bomb, containing 907 kg (1 ton) of fertiliser explosives, which was detonated on April 24,1993, at Bishopsgate in London. One person was killed and 30 injured; damage to buildings amounted to £600 million.