Bognor Regis will be given £1.6m to boost the economy and improve public spaces. The Sussex town secured the grant from the Coastal Communities Fund, a scheme to regenerate seaside towns and villages.
Newhaven will also receive £1.9 million from the Fund.
The Sussex towns secured the grants after successful bids by Lewes District Council and Adur District Council for a share of £27.7 million of funding for more than 50 projects across the UK.
In Newhaven the money will be spent on developing existing Denton Island facilities including new Innovation Space at the Enterprise Centre, more nursery space, new training rooms and a café.