For most, the perfect end to any holiday is a few days on the beach and from Phnom Penh the Cambodia coast is 3 hours away. If you're a true beach lover we'd recommend that you hop on a boat and head to Koh Rong, 1 hour from the mainland and ringed by powder white beaches and little else. If the beach isn't the main consideration and you just want to relax in a beautiful environment then Kep will hit the mark. This laid back seaside resort found fame as a Khmer retreat offering an atmospheric stay by the sea. Except for a crab market and some simple restaurants there is little else here, but you can visit outlying islands.
Day 1: After the group tour transfer to your choice of beach resort for 5 nights (or less / more)
Days 2-5: 4 days to relax on the beach, enjoy the hotel's facilities & perhaps take an optional excursion
Day 6: Perhaps extend your beach stay? Otherwise airport transfer and overnight flight home