The Magpies are currently short of cover in the left-back position, as Paul Dummett is sidelined with a hamstring injury, while the likes of Chancel Mbemba, Javier Manquillo and Jesus Gamez have all had to fill in at various stages of the season.
Japan international Nagatomo would certainly be a worthy arrival at St James' Park, but he has featured on a regular basis for Inter this season and reports in Italy have suggested the Nerazzurri have offered him a new contract.
However, those reports have also noted the 31-year-old is yet to sign the proposed new deal and he could be open to a new challenge in the Premier League.
Newcastle are not the only English club to be linked with Nagatomo, as Burnley and West Brom are also believed to be interested in his services, although a lot could depend on whether he can maintain his current position in Inter's first-team.
The experienced defender's current contract at the San Siro is due to expire in the summer of 2019 so any potential suitors would have to pay a transfer fee to bring him in.