A new conservation area is to be created and an existing one extended in a bid to protect the breeding grounds of threatened seabirds.
Species including little and common terns, avocets, ruffs and migratory knots could benefit from the Special Protected Areas (SPA).
The Teesmouth and Cleveland Coast SPA, near Middlesbrough, is being extended by 42 sq miles (109 sq km).
A new Solent and Dorset Coast SPA will cover 344 sq miles (891 sq km).
The two areas, which join 47 already in existence in England, aim to protect rare and vulnerable seabirds from human activity, such as fishing or recreation.
The Solent and Dorset conservation area, stretching from Worbarrow Bary to Middleton-on-Sea, is expected to benefit almost 1,000 pairs of three species of tern.
It is the fifth most important foraging site in the UK for little terns and the seventh most important for common terns during the breeding season.
The Teesside extension will protect more than 35,000 birds, according to the Department for Environment Food & Rural Affairs (Defra).
Environment minister Rebecca Pow said: "We have already protected important nesting sites for seabirds, such as the little tern, and these new and additional protections... will help the coastal environment recover, develop and, importantly, thrive."
Natural England chairman Tony Juniper added: "These new areas will ensure that species of conservation concern, such as terns and waders, have access to secure food sources, including during their critical annual breeding seasons."
The RSPB said the announcement "will be a first step in tackling this growing problem".
The UK plays host to about 25% of Europe's breeding seabirds and the SPA network conserves breeding sites and foraging grounds for an estimated 70% of UK breeding seabirds and 37% of UK non-breeding water birds.
An SPA is designated under EU law, but officials said the protected areas would be maintained after Brexit.