The Mosquito was very versatile, with almost 50 variants over the course of its production (albeit not all built in quantity). Its main roles were bomber, photo reconnaissance, fighter/bomber, and night fighter, with different noses to suit the roles.

As a bomber the Mosquito carried no guns, relying on speed instead, and had a glass nose for the observer when acting as bomb aimer: "... the observer normally sits beside the pilot where he carries out his duties as navigator, W/T operator and look-out. The bomb sight is situated in the nose forward of the pilot and it is necessary for the observer to move into this position before bombing. A clear view panel is provided for bomb aiming." (Air Fighting Development Unit, Report No. 39.) Photo reconnaissance versions had the same glass nose:

• De Havilland Mosquito Mk IVs
• Mosquito PR Mark XVI, MM341

As a fighter/bomber it had a solid nose with four .303" machine guns, and four 20mm cannon (or, on the Mk XVIII, one six-pounder cannon) were mounted in the forward section of the bomb bay:

• Mosquito FB Mark VI, HJ719
• Armourers prepare a De Havilland Mosquito FB Mark VI of No. 23 Squadron RAF for night operations at Pomigliano, Italy.
• The Mosquito Mk.XVIII carries four .303 machine guns and one six-pounder cannon

Night fighter variants carried a radar in the nose; early versions using AI Mk IV radar with external aerials could also fit machine guns, later versions with larger radar sets such as the AI Mk VIII and Mk X only had the cannon with a radome covering the radar:

• Mosquito NF Mark II, DD609, fitted with AI Mark IV aircraft interception radar
• Mosquito NF Mark XVII, DZ659 ... the aircraft has been fitted with SCR.720/729 (AI Mark X) aircraft interception radar in a universal radome