Great oportunities exist for cycling the whole area but on the Isle of Portland itself you’ll have to be fit as there are large steep hills, excellent training for other cycling events!
From the causeway onwards towards Weymouth and the mainland there’s cycle tracks. From the Sailing Academy onwards you can cycle the very gentle Rodwell Trail (the old railway track) right the way in o the heart of Weymouth and there are many more cycle tracks to take cyclists safely around most areas of Weymouth, along the sea defences to Preston or further inland up to Dorchester, the county town of Dorset.