The measures are being introduced to improve road safety and bring town into line with other parishes.
Workers from the parish have been busy erecting new maximum-speed signs over the past few weeks, most of which have been covered in black plastic until now.
Speed limits are also changing on roads in Grouville.
A 30mph zone will be introduced along the coast road from near the Pembroke pub to the St Clement parish boundary, near La Rocque.
Meanwhile, routes around the Grouville section of Gorey Village and roads to the south and east of Grouville school will become 20mph zones.
The changes were requested by the parishes following parish assemblies, and all roads around the Island will have their limits reviewed before the end of 2019.
