Monday's surprise announcement ends speculation that the Household Cavalry officer would leave the military next year to become a full-time working royal. His decision means that an engagement to sweetheart Kate Middleton is also probably some way off now.
The 18-month course to prepare him for the hazardous job begins in January, followed by a further 30-month minimum attachment to SARF. Once trained to pilot Sea King helicopters, the second-in-line to the British throne will fly missions such as rescuing sailors in trouble and airlifting people from flood areas.
William, 26, was bitten by the flying bug during an attachment with the RAF earlier this year. The Prince said he wanted to "build on the experience and training I have received to serve operationally – especially because, for good reasons, I was not able to deploy to Afghanistan this year with my squadron".