Garth Hill College students Katie Turney, 13, and Rachel Arnaboldi [CORR], 14, will be part of a 20-strong team of Girl Guides, picked from groups across Berkshire, to travel to the Ulfljotsvatn Scout Centre, near Reykjavik, next August.
The trip will include horse riding, walking on a glacier and hiking but comes at the hefty price-tag of £1,000 - which each participant must find themselves.
In order to do so, the pair have organised numerous cake and car boot sales, raffles and tombolas, and have even contacted local business about donating raffle prizes.
But their big fundraising event is still to come.
Both youngsters, with help from friends, family and the 1st Warfield Guides - which they belong to - have booked out the Tea House, in Broadway, and will be selling refreshments, bacon butties and cakes on Saturday, December 8, from 10am-4pm.
Katie's mum, Christine Turney, helped organise the event and added: "There will even be a tombola and small gifts for sale as well, with Father Christmas around to lend a hand!"