From today (3 January), it will cost more to post a letter, but up to 50% less to send a parcel, even a large one.
Guernsey Post say the rates reflect how customers use the service.
Sending a letter, which has steadily declined in popularity, will become more expensive, but the money gained will help support the parcel post.
Those rates will either stay the same, or decrease in price, by as much as half.
Parcel post has increased in volume over the years due to the popularity of online shopping.
It will now cost £1.20 to send a letter to the UK, while parcel post rates stay the same or get cheaper:

Returns for goods bought online will be charged at a flat £5 for up to 10kg, while there's a 50% drop, or £30, in the price of a 30kg parcel.

Protestors to meet deputies ahead of Guernsey's GST debate
Venue change for World Cup semi-final screening in Guernsey
Discarded glass blamed for Little Sark fire
Appointment of Guernsey's first female Bailiff
Sensitive demolition at Guernsey's largest building site to begin soon
Private fostering laws could be updated in Guernsey and Alderney
Guernsey big screen for World Cup Semi-Final sold out
Hundreds protest against a goods and services tax for Guernsey