On 10 June, the "Illustrious" and the escort carrier put to sea to simulate another airstrike on Sabang as a means of distracting the Japanese while the Americans were attacking airfields in the Mariana Islands and preparing to invade the island of Saipan. For the planned attack on Port Blair in the Andaman Islands in mid-June her air group was reinforced by the 14 Corsairs of 1837 Squadron; six Barracudas from No. 21 TBR Wing were landed to make room for the additional fighters. On 21 June, the ship launched 15 Barracudas and 23 Corsairs against the airfield and harbour of Port Blair. Two of the Barracudas were forced to return with engine trouble before the attack began and another was shot down over the target. In addition, one Corsair was forced to ditch; the pilot was rescued by a destroyer. Bad weather degraded the accuracy of the Barracudas and little damage was inflicted aside from a few aircraft destroyed on the ground and a few small craft sunk in the harbour. With over 50 aircraft airborne at one point, the British realised that a single deck accident might result in the loss of every aircraft in the air because there was no other carrier available to land aboard. The carrier and her escorts arrived back at Trincomalee on 23 June where 847 Squadron was merged into 810 Squadron a week later.