At the end of the North African campaign in May 1943, there were three P-38 groups in North Africa – the 1st, 14th and 82nd Fighter Groups. These three units would remain in the Mediterranean, and play an important part in the Allied invasion of Sicily and mainland Italy.
The first target for the allies was the Italian fortress-island of Pantelleria. All three P-38 groups took part in the bombing campaign against the island, starting on 1 June 1943. On 11 June the defenders of Pantelleria surrendered, making the planned land invasion of the island superfluous.
After Pantelleria attention turned to Sicily, where the allies landed on 10 July. Once again all three P-38 groups were involved in the invasion, mostly from Tunisia, although the 82nd FG operated from Libya. This period saw the P-38 come up against the last generation of Italian fighter aircraft, as well as the standard Luftwaffe types.
The three units then moved to bases on Sicily, and began to prepare for the invasion of mainland Italy. This involved a large number of ground attack missions against enemy airbases and communication targets, with the P-38s acting as fighter bombers. A temporary diversion came in October 1943, when the 1st and 14th FGs were detached to take part in the unsuccessful British invasion of the Dodecanese Islands. This set the tone for much of the rest of the war. Once the P-38s were established in Italy, they spent much of their time escorting bombers to southern Germany or across the Balkans, attacking targets in Yugoslavia from October 1943.
The P-38 was still important as a fighter aircraft. In September 1943, the Allies invaded southern Italy. Of all the allied fighters involved in the invasion, the P-38 had the longest range, allowing it to spend an hour over the invasion beaches (including ten minutes of combat). Once the allies were established on mainland Italy, the P-38 groups followed, spending the rest of the war following the allied armies as they slowly moved up the Italian peninsula. By the end of the war, these three groups represented the largest concentration of P-38s in the European theatre.