England men will start their home summer with two Tests against world's number one side New Zealand.
The first Test at Lord's will begin on 2 June, and the second at Edgbaston on 10 June.
Three Twenty20s against Sri Lanka - two at Cardiff and one at Southampton - have also been added to England's schedule.
Joe Root's side will play five Tests against India after white-ball series against Sri Lanka and Pakistan.
"The prospect of us taking on the world's two top-ranked Test nations in New Zealand and India this summer is something for us all to savour," said ECB chief executive Tom Harrison.
New Zealand, who went top of the International Cricket Council rankings with their series win against Pakistan over Christmas, drew a two-Test series 1-1 on their most recent tour of England in 2015.
England are scheduled to play 17 Tests in 2021 - two on their current tour of Sri Lanka, four in India, seven at home this summer and four in Australia starting in November.
England men's 2021 summer schedule
New Zealand Tests
2-6 June: First Test, Lord's
10-14 June: Second Test, Edgbaston
Sri Lanka T20s & ODIs
23 June: First T20, Sophia Gardens
24 June: Second T20, Sophia Gardens
26 June: Third T20, Ageas Bowl
29 June: First ODI, Emirates Riverside
1 July: Second ODI, Kia Oval
4 July: Third ODI, Bristol
Pakistan ODIs and T20s
8 July: First ODI, Sophia Gardens
10 July: Second ODI, Lord's
13 July: Third ODI, Edgbaston
16 July: First T20, Trent Bridge
18 July: Second T20, Emerald Headingley
20 July: Third T20, Emirates Old Trafford
4-8 Aug: First Test, Trent Bridge
12-16 Aug: Second Test, Lord's
25-29 Aug: Third Test, Emerald Headingley
2-6 Sept: Fourth Test, Kia Oval
10-14 Sept: Fifth Test, Emirates Old Trafford