Mako: Island of Secrets is a spin-off of H2O: Just Add Water, set several years after the events of its predecessor, and was created by Jonathan M. Shiff.

The show went through several title changes before release: it was first announced as Mako: Island of Secrets, then referred to as Secret of Mako Island, and finally marketed internationally as Mako Mermaids.

Filming for the first series was originally scheduled to begin in April 2012 but was postponed to early May 2012, and shooting continued through 12 October 2012.

Production of the first 26-episode series cost a total of A$12.3 million.

A second series was confirmed by producers before the first series had even finished screening, and its production was contingent on funding from Screen Australia.

Netflix served as the exclusive internet television provider for the series in partnership with Shiff Productions, and split the second series into two parts released separately in 2015, which Netflix labelled as series two and series three respectively, causing series three (as aired in Australia) to appear as Season 4 on Netflix.

The third series introduced a Chinese mermaid character, Weilan, played by Linda Ngo, and featured a special guest appearance by Cariba Heine reprising her H2O: Just Add Water role as Rikki Chadwick in the final two episodes.

A movie sequel was planned to follow the conclusion of the series, but those plans have been put on hold indefinitely.