Clark said she would take some time out from travelling to spend more time at home before returning to the industry "in some capacity".
David Gooch, Iglu.com chief executive, paid tribute to Clark, describing her as an "incredible asset to the business", flagging in particular her contribution to launching and growing Iglu Cruise.
"She is widely recognised as one of the most influential figures in the industry, and she will be sorely missed around the business," said Gooch. "We wish her well in her future endeavours.”
Clark, who has been with Iglu for 19 years, said her departure had been planned for some time, having already stepped back into a less operational role.
"I love Iglu, but I want to spend less time travelling and some more time at home," she said. "I intend to enjoy a few months off and then will definitely make a return to the industry in some capacity.
"I’d like to thank my colleagues at Iglu and Planet Cruise, all the cruise line partners, and everyone in the cruise industry for making the journey so much fun over the years. A particular highlight for me was winning the award for outstanding contribution to the UK cruise industry from CLIA.”