The 23-year-old was very impressive for the England Under-21s at the European Championship finals in the summer and David Moyes will submit an offer for him next month.
According to reports, the Hammers are prepared to offer around £20m for the defender. The report claims that Mawson is a key target for West Ham.
However, it will be interesting to see whether Swansea are willing to sanction a sale. The Welsh outfit are fighting relegation after selling the likes of Sigurdsson and Llorente in the summer and they will not want to lose Mawson now.
Furthermore, the Swans are looking for a manager after the sacking of Clement and they will not want to sell any player before a replacement manager comes in.
West Ham have improved at the back since the arrival of Moyes but the Hammers are in desperate need of reinforcements.
Mawson has 18 months remaining on his current deal and the Swansea are hoping to agree on a new deal with the player. The 23-year-old signed from Barnsley for a fee of £5m in August last year and has become a key player at the back for the Swans. He would be a very good addition to David Moyes’ side.