SPEAR weighs less than 90 kilograms (200 lb) with a length of 1.8 metres (5.9 ft) and a diameter of 180 millimetres (7.1 in). SPEAR is guided by inertial navigation and GPS as well as a two-way datalink. This with a multimode seeker head for terminal guidance which includes millimetric wave radar, semi-active laser and combined modes^. The weapon is propelled by a Hamilton Sundstrand TJ-150 turbojet (the same engine as used in the JSOW-ER and MALD) which when combined with a folding wing kit and three deployable tail-fins, provides an engagement range reportedly in excess of 140 kilometres (87 mi). The size of SPEAR's warhead is not public, but is believed to be smaller than the SDB-II's approximately 105 pounds (48 kg) warhead. According to MBDA, SPEAR is designed to engage various ground targets including armoured vehicles, self-propelled artillery, air defences, ballistic missile launchers and defended structures, but also naval targets. MBDA produced an animation in 2015 showing SPEAR engaging small vessels including LCACs.

SPEAR will be integrated with the F-35 Lightning's Block 4 software package. Whilst SPEAR has been integrated onto the Eurofighter Typhoon for testing purposes, it is still unclear if formal integration will occur. Mock-ups for the UK's future sixth-generation fighter 'Tempest' being developed under the Global Combat Air Program (GCAP) with Japan and Italy have been shown with SPEAR as part of the aircraft's possible future arsenal alongside the (FC/ASW). Four SPEARs and an air-to-air missile (Meteor) will fit in each of the two internal weapons-bays of the F-35B when in an air-to-surface configuration. No images have yet been revealed of external carriage capability for the F-35B with all current renderings and models showing only internally mounted weapons. MBDA had previously shown artwork of a four-missile launch rail on a single Typhoon weapon station. This has been revised to instead a tri-rail configuration.

Networked swarm capability for SPEAR missiles is in development In 2023, MBDA announced that SPEAR would be integrated into Orchestrike, MBDA's collaborative effector system utilising AI to allow multiple smart munitions to work in concert with one another. At the Farnborough Airshow 2024, MBDA confirmed that the SPEAR product line would be the first to receive this capability.