To understand the naval war in the Mediterranean, a good understanding of the naval geography of the area is necessary. This map will be helpful - British bases are marked in blue, while Italian bases are marked in red. The Royal Navy's main bases in the Mediterranean were Gibraltar, Alexandria and Malta. Malta was so close to the Italian airfields in Sicily that it was not feasible to base heavy units there; as such, the Mediterranean Fleet spent most of the war operating from Alexandria, while Force H was based at Gibraltar. The Italian Regia Marina had numerous bases in Italy and Libya. This should immediately show one of the difficulties the British faced. When operating against Axis shipping to North Africa, they were operating at the end of a comparatively long logistical tether. They were operating under Axis air cover, increasing the risk to their ships. They also faced a further difficulty: because Gibraltar and Alexandria are at either end of the Mediterranean, it was harder for them to concentrate forces against the Italian fleet. Finally, the RN had to support and supply Malta, which, though easy to attack, provided a useful air and submarine base. Put together, this made it difficult for the Royal Navy to establish a constant blockade against Axis shipping running between Italy and North Africa. There were frequent attacks by submarines, aircraft and surface shipping against Italian convoys, but these could not be made constant. The Italians could also put together sufficient forces to protect the convoys against all but the most determined attacks.

There were frequent battles between the RN and the Regia Marina in the Mediterranean focusing on Italian convoys. The first such action was a raid by British cruisers on a force of Italian destroyers carrying troops to North Africa; called the Battle of the Espero Convoy, the British sank one of the three destroyers, while the other two escaped behind a smoke screen. On the 9th July 1940, the Battle of Calabria was fought. One of the few fleet actions of the Mediterranean war, it began with both the RN and RM escorting convoys, the British to Alexandria and the Italians to Libya. Both sides were alerted to the other's presence by air reconnaissance, and moved to intercept the other's battlefleet. A short, inconclusive action was fought, with neither side really coming off better. In April 1941, a British destroyer flotilla intercepted the Italian Tarigo convoy. The British sank five merchants and three destroyers, in return for the loss of the destroyer Mohawk. In November, a similar success was achieved against the Duisberg Convoy. The next month, four British destroyers ambushed two Italian light cruisers carrying fuel cargoes to North Africa, sinking both off Cape Bon. A few days later, the First Battle of Sirte was fought. A light British force escorting a fast merchant to Malta encountered a heavier Italian force escorting a convoy to North Africa. Neither side wished to seek action, and so only a short action resulted, with little damage done. On the 19th, the Italians pulled off a major coup, using human torpedoes to heavily damage two British battleships in Alexandria Harbour. Combined with the loss of HMS Barham to a German submarine in November, this allowed the Italians to gain maritime superiority for much of 1942; with these losses, Mediterranean Fleet had lost three of its four battleships. Further complicating the British position was the loss to mines of several ships from Force K, the RN's main surface raiding force in the central Mediterranean. These losses meant that the Italians were able to run convoys practically undisturbed by surface raids during 1942. However, in December 1942, a British force completely destroyed an Italian convoy at the Skerki Bank. 1943 saw two main successes for surface raiders; the Cigno convoy, where the British sank an Italian destroyer and forced the convoy to withdraw in exchange for one destroyer sunk, and the Campobasso convoy, where the eponymous merchant and her escort were sunk.

Combined with these surface actions, the British maintained a constant submarine and air presence in the waters between Italy and North Africa. The 10th Submarine Flotilla, based in Malta, was key to this. Its submarines made numerous attacks on Axis shipping to and from North Africa. The effectiveness of these attacks is demonstrated by the fact that it included the most successful British submarines of the war; submarines like Upholder, which sank just under 100,000 tons of Axis shipping. However, the 10th Submarine Flotiilla was never strong enough to successfully blockade the North African coast alone. It was also hampered by the precarious position of Malta, which was low on supplies, food and fuel. Aviation from Malta suffered from similar problems.

The Italians could not stand up to Mediterranean Fleet's full strength in a fleet action. Mediterranean Fleet had, at its peak, four battleships and two aircraft carriers. It could also call on Force H, with an extra battlecruiser and aircraft carrier, to reinforce it. The Regia Marina, meanwhile, had four essentially obsolete battleships, and two modern battleships. Following the Battle of Taranto, one of the older ships was a complete loss. The Regia Marina was less skilled than the RN, as demonstrated well by the Battle of Cape Matapan. The British had superiority in radar, training, and morale. The Regia Marina also suffered heavily from a lack of fuel, which prevented it from acting to full effectiveness. These fuel difficulties, along with British control of Gibraltar, and the fact that the Italian ships were designed for the calm Mediterranean rather than the stormy North Atlantic, explain the fact that there was little naval coordination and cooperation between Germany and Italy.