The Sea King's Daughter by Barbara Michaels
This was my third Barbara Michaels for Halloween bingo, and I am using it to claim Fear the Drowning Deep, which is also the final square to black out my bingo board. It is a bit of a stretch, but involves a main character who goes to the island of Thera (now called Santorini) to spend the summer diving with her archaeologist father, looking for the remains of Minoan ships that would've sunk after the eruption of Thera.
There are lots of references to Greek mythology, including Ariadne (the MC's full name, although she goes by Sandy), Poseidon, and Persephone. The MC nearly drowns while she is searching the seabed for artifacts, which is how I justify applying this book to Fear the Drowning Deep.
There is very little supernatural influence here, rather this is quite similar to a Mary Stewart romantic suspense novel, so those of you who enjoy reading Stewart might like this one quite a lot. There is a strong romantic subplot with an appealing young archaeologist who meets Sandy during her time on the island. There's also a semi-bizarre encounter with a cult of village women who are interested in using our pair for a fertility rite, which threw me for a bit of a loop.
And that's a wrap for my first bingo card! I made my goal of blacking it out by October 1. My second card is going to be a woman only affair!