Venn has been named associate vice-president, sales and distribution, reporting to chief commercial officer Stuart Allison.
Vice-president brand and marketing strategy Rob Scott has also been handed a wider marketing remit, with greater responsibility for long-term growth and brand strategy.
"This is a very well deserved promotion for Ruth, whose experience has placed her at the forefront of the cruise industry for many years," said Allison.
Allison continued: "Under her leadership, our 25-strong sales team will continue to broaden and deepen our trade distribution channels."