The £20m Naval Service Recovery Pathway Expansion Programme facility will be built at Devonport Naval Base in Plymouth and is the first of its kind in the south west.
Construction is due to start next month on a 60-bed accommodation building, including family rooms and recreational spaces.
Phase two will see the construction of a 25m, six-lane swimming pool, hydrotherapy pool, gymnasium and consulting rooms.
Brian Talbot, Interserve managing director of Defence, said: “Help for Heroes want to have a facility that enables them to help each individual hero that has contributed to helping to keep our country safe.
“The organisation wants to spend its time fundraising and continuing to put its energies into the great work it is already doing.
“Interserve is a company which can supply expertise to every stage of the delivery process, from initial design to ongoing maintenance and support, and has a proven track record of this approach to help its clients save time, money and hassle.”