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.

Sensitive demolition at Guernsey's largest building site to begin soon
Guernsey big screen for World Cup Semi-Final sold out
Hundreds protest against a goods and services tax for Guernsey
Donations page set up for Sark's volunteer firefighters
Firefighters tackle gorse fire at La Corbiere
50 people evacuated from scene of fire in Portbail-sur-Mer
'Pause before paying' to avoid being scammed, islanders urged
Five Guernsey firefighters injured while travelling to assist with Sark fire