The stunning snapshots were taken by her friend, photographer George Barris, on Santa Monica beach on July 13, 1962, just three weeks before she was found dead at 36 in her Los Angeles bedroom.
The set also includes photos of Monroe in her Brentwood, California, home, reported Daily Mirror.
Eight of the prints, several of which show Monroe romping on the beach in a towel or bikini, are expected to sell for 8000 pound at Dreweatts & Bloomsbury Auctions in London on June 4.