Omeruo got interest from La Liga clubs but has finally completed a transfer to the latter until the end of the 2018/19 football season in June.
The 24-year-old defender has been loaned out by Chelsea again as he is not in the plans of new manager Maurizio Sarri who has available at his disposal senior options Gary Cahill, David Luiz, Antonio Rudiger and Caesar Azpilicueta.
Omeruo signed for Chelsea from Belgium First Division side Standard Liege in 2014 and has been loaned out to Eredivisie outfit ADO Den Haag Championship side Middlesbrough and Turkish Super Lig sides Kasimpasa and Alanyaspor.
The deal to Leganes confirmed that Omeruo will be at the Madrid based club until the end of the season with a clause for purchase based on performance.
Omeruo was part of the Super Eagles team to undefinedwhere he played two matches against Argentina and Iceland in the group stage and was part of the team to the 2014 FIFA World Cup.
He has played for Nigeria at the FIFA U-17 and U-20 World Cups and was also part of the Super Eagles team that won the 2013 African Cup of Nations (AFCON) in South Africa.
He joins international teammate Ola Aina