Service personnel will be able to apply for enhanced flexible working opportunities after the Armed Forces (Flexible Working) Bill became law on the 8th February.
The measures, which achieved Royal Assent on Thursday, will allow some military personnel to serve part-time for defined periods.
Consultation within the Armed Forces has found that personnel want more choice over the way they serve when their personal circumstances change, such as having young children, needing to care for elderly relatives, or taking on further training and education.
Personnel will also be able to restrict the amount of time they spend away from their home base and their families.
The plans, which will come into effect in 2019, are part of a range of measures the Armed Forces are implementing to become more modern and diverse.