The Siren & the Sea by Emma Elizabeth

After her bakery went up in flames, Maura left her homeland, Beitar, behind for the shores of the Vaporiad Sea. Though the locals warned her of the vicious sirens that made that coastline uninhabitable, she doesn’t take their warnings seriously… until an unfortunate slip sends her tumbling into the brutal, icy waves.

Siren prince Anatolius never quite fit into the role his fathers expected of him. Though he is meant to spend his days monitoring the northeastern coast, he finds himself watching the curious human he discovered inhabiting the old fisherman’s cottage. Watching her is the highlight of his day, until one afternoon he sees her fall into the unforgiving sea. He rushes to her aid, determined to get her out before the other sirens find her and punish her for entering their territory, only to find her as… an otter.
To keep Maura from facing the wrath of the other sirens, Anatolius claims she is his bride-to-be. The two must work together to navigate the delicate situation in the siren court and get Maura back home alive.

The Siren & The Sea is a standalone novelette set in the world of Domhan na Rùin. The three books in the series can be read in any order.