The 28-year-old has the country's driving silks, emblazoned with the silver fern, packed in his suitcase as he sets off today to compete with the world's best harness racing drivers.
Though Williamson is focused on the championship, he could be forgiven for ranking the world series second on the list of big moments he is approaching.
The winner of 780 races in New Zealand will compete in the 24-race competition while his fiance, fellow driver Charlotte Purvis, counts down the days until the due date for the birth of the couple's first child.
''Charlotte is due on the 10th of June. I am hoping the baby holds out until I get back.
''The last day of the competition in the 31st of May, so hopefully it all works out.
''Most of all, I just hope everything goes well for her while I am away. Luckily, she has all of the family there to support her.''
If everything goes to plan, Williamson will welcome his first child in his arms as a world championship-winning father.
Appropriately, it is a family connection that gives Williamson one of his biggest strengths going into the competition.
The five-day championship is made up solely of trotting races, which is a major advantage for a member of arguably New Zealand's most gifted trotting family.
''Sweden has some of the world's best trotters and I am looking forward to driving them. You'd think the class of horse I will be driving will be very high.
''No matter how things pan out, it is just a massive honour to be going and to put on the silver fern.''
Williamson said his father, Phil, New Zealand's all-time leading trainer of trotters, had given him some pieces of advice ahead of the competition.
''He has given me a few bits of advice. One of them was that if you can win one race, you can say you've beaten the best in the world.''
Just how Williamson will go about his quest for championship glory was murky as he packed his bags last night, he said.
''I won't know a lot about the horses and their form, so I will have to drive them on feel a little bit. Hopefully the trainers will be able to give some instructions. I have been told most of them speak English.''
Williamson said he would not be changing the often aggressive nature of his driving in the championship.
Should he need to talk tactics, he will not have to go far to seek the ear of a successful trotting driver.
With Purvis unable to travel to the championships, Williamson's good friend, multiple trotting group 1-winning trainer and driver Joshua Dickie, will accompany him to Sweden.
One thing is certain to be highly unusual for Williamson at the world championships.
The popular reinsman's quest for the world title will start on a note that could be considered controversial by his most loyal followers.
Williamson will drive in a race for the first time without his signature gold helmet.
Instead, he will wear a silver fern-emblazoned black cap that matches his national driving silks.
