After sharing birthday cake, the GSPCA team travelled to Portlet to release seal pups back into the wild.
On 14 February 1873, a Society for the Prevention of Cruelty to Animals was established.
150 years later, Guernsey now knows the charity as the GSPCA.
In celebration of the big anniversary, the team gathered to share a purple-themed cake.
They then travelled to Portlet to release two seal pups which they had nurtured back to health.
Both were discovered in the autumn of 2021 - Luna C in Guernsey and Aurora in Jersey.
Manager Steve Byrne says they were both very ill and underfed when they arrived, but they've made a good recovery:
"On this wonderful sunny day, we've released two seals which have been with us since last year, so the last two seals from the last season.
It's wonderful seeing them being released back where they belong, having had to go through so much and being so poorly when they arrived."
The charity is currently amid a fundraising campaign to build a new wildlife hospital at its HQ in St Andrews.
Mr Byrne says the completion of this project and continuation of the animal shelter's work is heavily reliant on the generosity of islanders:
"We're asking islanders to support our work.
One of the best ways they can do that is to sponsor a kennel and become a part of our history for the future."
Pubs can apply to stay open later to show World Cup games
Landowners reminded to clear Guernsey's streams of vegetation
Guernsey homelessness charity 'deeply concerned' at rising support need
Plans lodged to improve Guernsey's sea water Children's Pool
States record £45M surplus, but still warn of Guernsey's funding gap
Warmest Guernsey spring on record
Parent challenges Guernsey school's attendance rule after Prom exclusion
Survey to expose barriers to adult learning in Guernsey
