There are 1 book by Helen O'Clery on BookOrb. A strong starting point is The Mermaid Reader. The bibliography below is in publication order, with series grouped in reading order.
Standalone books
Frequently asked questions
How many books has Helen O'Clery written?
BookOrb lists 1 book by Helen O'Clery.
Where should I start with Helen O'Clery?
A good starting point is The Mermaid Reader.
What is the Helen O'Clery books in order list?
In publication order: 1. The Mermaid Reader.