Viki Patel popped the question to Rebecca Chaukria and gave her the white gold and diamond ring during a trip to the Lake District on Saturday.
Two days later, while on a jetty overlooking Windermere, it slipped off her finger and fell into the water.
They feared it was lost forever, but freediver Angus Hosking was able to locate it after a 20-minute search.
Read BBC and CNN
