The 20-year-old arrives from Danish Superliga club FC Nordsjaelland, for whom he has played since January 2020.
Adingra, a product of Ghana’s Right To Dream Academy, scored 10 goals in 33 appearances last season.
Brighton technical director David Weir said: “We’re delighted to welcome Simon to the club.
“He’s an exciting young player who has had a terrific start to his career in Denmark.
“He’s a creative offensive player who can play on both sides and is very good in one-on-one situations.
“He’s a talented young player who we’ve had an eye on for a while, and we’re looking forward to helping him with his development.”
Last week Brighton agreed a £9.5m deal for 18-year-old Paraguay star Julio Enciso, who arrived on a four-year contract.
Check out the latest Premier League transfer speculation below...
![West Ham have made an offer to Jesse Lingard’s representatives over signing the player on a free transfer. (Sky Sports)](https://www.thestar.co.uk/jpim-static/image/2022/06/25/22/GettyImages-1392414425%20%282%29.jpg?crop=3:2&width=800)
1. Hammers make Lingard bid
West Ham have made an offer to Jesse Lingard’s representatives over signing the player on a free transfer. (Sky Sports)
![Newly-promoted Fulham have made an offer for Wolfsburg right-back Kevin Mbabu. (Tutto Mercato Web)](https://www.thestar.co.uk/jpim-static/image/2022/06/25/22/GettyImages-1384744266.jpg?crop=3:2&width=800)
2. Fulham make Mbabu offer
Newly-promoted Fulham have made an offer for Wolfsburg right-back Kevin Mbabu. (Tutto Mercato Web)
![Arsenal want Ajax centre back Lisandro Martinez but the Dutch club have raised his price tag above £35m amid interest from Manchester United. (Daily Mail)](https://www.thestar.co.uk/jpim-static/image/2022/06/25/22/GettyImages-1401685215.jpg?crop=3:2&width=800)
3. Gunners target Martinez
Arsenal want Ajax centre back Lisandro Martinez but the Dutch club have raised his price tag above £35m amid interest from Manchester United. (Daily Mail)
![Jose Mourinho’s Rome and La Liga outfit Sevilla are on the trail of Brighton defender Joel Veltman. (Sky Sports)](https://www.thestar.co.uk/jpim-static/image/2022/06/25/22/GettyImages-1398660466.jpg?crop=3:2&width=800)
4. Roma plot Veltman raid
Jose Mourinho’s Rome and La Liga outfit Sevilla are on the trail of Brighton defender Joel Veltman. (Sky Sports)