The first prize-winning ticket, which was issued in Jersey, will get £483,795, while the second prize of £50,000 was issued in Guernsey.
A full list of the winning ticket numbers can be viewed at www.cilottery.org.
Jon Taylor, Head of Lottery for States of Guernsey said: “I urge participants to double-check their tickets. Participants have 12 months to claim their prize.
“After this period, the funds are disbursed to worthy causes and charities through the Social Investment Fund in Guernsey and the Jersey Community Foundation and Association of Jersey Charities in Jersey.”
The winning numbers can also be checked at two independent lottery checker apps lotterychecker.je and lucky.je