The Blyth Valley is dissected by National Cycle Route 1 north-east/south-west through Halesworth.
Check out the Cycling Guides produced by the Suffolk Coasts & Heaths AONB.
DiscoverSuffolk has a very useful free App which you can download to assist with walking and cycling routes - and lots of other info.
The Halesworth Wheel cycle route with Halesworth at its centre, around 19 miles or 23 miles including the loops. Spokes from the centre to the perimeter allow the choice of longer or shorter cycle rides tailored to individuals’ choice.
Deeper into the countryside is the 34km Laxfield Circular Route.
Mainly on quiet country lanes, the many cycle routes are well-signed for cyclists and are never far from interesting village stops where refreshments can be found. Good exercise and something all the family can join in!
Consider joining the ever popular Suffolk Historic Church Trust Ride & Stride
As a point of interest, the North Sea Cycle Route is established in all the countries bordering the North Sea: Belgium, the Netherlands, Germany, Denmark, Sweden, Norway, Scotland – and England and goes right through the Blyth Valley!