Boeing has been awarded a $2.2bn contract for delivery of at least 17 P-8A Poseidon maritime patrol aircraft.

The agreement — signed with the U.S. Navy, the Royal Australian Air Force and the U.K. Royal Air Force — also includes options for 32 additional aircraft, as well as money for long-lead parts for future orders. If all options were to be exercised , the total contract value would be $6.8bn.

The Navy will receive 11 aircraft, while Australia will expand its P-8A fleet with four more. The U.K.’s first two P-8A jets are part of the agreement, with first delivery set for 2019. Boeing so far has delivered 53 Poseidons to the Navy and two to the Royal Australian Air Force.

The RAAF plans to ultimately operate a fleet of 15 Poseidons, 12 of which are due to be delivered by March 2020. Like the U.S. Navy, the RAAF will operate its P-8As in combination with the MQ-4C Triton unmanned aircraft, a derivative of the Global Hawk.

The RAF is acquiring nine Poseidons, urgently needed to close a glaring gap in U.K. defence capability that has existed since the abandonment of the problem-plagued Nimrod MRA4 programme in 2010.

The Indian Navy currently flies the P-8I variant of the aircraft. They have received eight aircraft to date and in July 2016 signed a contract for four additional P-8Is.