The event will also be an educational trip with an opportunity to visit the Aboriginal Cultural Centre, a wildlife park and test their courage on the daunting Sydney Harbour Bridge Climb.
But Sean and Daniel are not keen to talk about the off-track events so much. For them it is all about the racing.
Two Saturdays ago they took on the best runners in the country at the New Zealand trials at Mt Smart Stadium. Auckland officials expected Dion Wallwork from Pakuranga to show the Katikati twins who was number one over 1500m.
That did not go quite to plan.
Daniel won the race in a record time of 4m 37. 25s, with Sean second in 4:40:98 and Dion trailing way behind.
"We were more nervous this time because everyone was talking about this kid called Dion and how he could go a lot faster. We beat him by 23 seconds," Daniel said laughing.
The twins did not give too much away when they were talking but their huge grins said plenty about what they thought of cleaning up Auckland's best runner by such a margin.
It makes you stronger, gives you more energy and makes you faster and fitter.
Also at the trials, Daniel won the 800m with another quick time of 2.19.92 - his fastest time - just ahead of Sean in 2.20.61. Seriously good times for 11-year-olds by any standards.
Their performances followed on from their remarkable 1500m times last year, when they both went under the five-minute mark - a rare feat in their age group.
Aside from their 800m and 1500m distances, in Sydney Daniel will compete in the 100m and long jump with Sean contesting the long jump and high jump.
Daniel was surprised when he was selected in the sprint event although he does have a personal best which will be competitive.
"I am not a sprinter and haven't done much but I have done it under 15 seconds."
Earlier this year the twins made an impact competing for Katikati College at their first AIMS Games. They finished first and second in the cross country race in yet another record time.
They love off-road running as much as the main track competitions.
"I like it because there are more people running," Sean said.
"It makes you stronger, gives you more energy and makes you faster and fitter."
They both admire Kiwi Olympic 1500m medallist Nick Willis - an ideal role model for two young athletes with an equal amount of natural talent and bright futures.
But raising funds to get to Sydney is proving to be a challenge for the Nicholson twins.
If you can help contact their mum Jackie on email cajodase@gmail.com.