Mommsen attended Hilton College in KwaZulu-Natal. Here he was not only a member of the 1st XI cricket team but also of the 1st XV rugby team and went on to represent South Africa School Boys for both sports. In 2006 Preston went on a cricket and rugby scholarship to Gordonstoun School in Moray, Scotland for the summer and winter terms. During this time he became the first school boy to score 1000 runs in that season. It was while he was at Gordonstoun that he got the chance to play for Kent 2nds.

Early career

Mommsen had a brief spell at Kent but only managed to make two appearances for the county's 2nd team. After leaving Gordonstoun (attended by HRH Prince Charles, Zara Phillips & Peter Phillips), Preston moved permanently to Scotland, living in Edinburgh. It was here that he started playing for Carlton. After four years living in Edinburgh he qualified for the Scottish National Team and was subsequently called up in June 2010 after impressing at club level.^[6]

2011 Season

The 2011 Season is the first full season Mommsen has been eligible for Scotland. As such he was selected in Scotland's CB40 squad and got off to a good start with two 50's and an average of 62.2 after the first 7 games of the season.^[1] Mommsen went on to finish the season with 408 runs at an average of 58.28 in the competition. As a result of his form, Scotland offered a full-time contract for the following year and he spent time at both Kent and Northamptonshire who were interested in signing him.^[7]

2011/12 Winter

Having signed a full-time contract with Scotland, Mommsen has been included in their winter tours of Namibia and India, where in the latter Scotland start their campaign to qualify for the 2012 World twenty20. He marked the occasion with his first international hundred scoring 102 off 192 balls in the first 4-day game against Namibia in Windhoek.

2013 Season

In June 2013, Mommsen has been named as captain of a youthful Scotland squad to take on Australia A in a first-class four-day fixture in Edinburgh.

Cricket Scotland named him replacement to Scotland Captain Kyle Coetzer took over at Grange Cricket Club in Edinburgh.

Mommsen was ruled out of Scotland's 2013 World T20 qualifying campaign in a blow to their chances of winning a place in Bangladesh in March 2014. He had a pelvis injury and won't be able to join his squad for the qualifiers in the UAE.

ICC World Cup Qualifiers

Mommsen went on to guide the innings at No.4, reaching a maiden List A ton as Hong Kong managed to hold on to a 17-run victory over Scotland at Queenstown Events Centre bringing a losing start for Scotland’s Wo