The Blaugrana are extensively tracking defenders to overhaul their defence options at the end of the current campaign, with Mundo Deportivo stating the three are top of sporting director’s Robert Fernandez’s list.
Slovakian international defender Skriniar, whom Inter only signed from Sampdoria this summer, is said to top the list alongside Koulibaly of Napoli and German-based Upamecano.
Skriniar has made an impressive start to life at the Milanese giants since his €25m summer switch, scoring twice in 11 appearances.
Koulibaly, a Senegalese international, initially joined Napoli from Genk in 2014 and has played a central role in helping them to top spot in Serie A.
19-year-old Upamecano, a French youth international, is highly-rated in Leipzig, where he has made 15 appearances.
Barca are keen for defensive reinforcements with Thomas Vermaelen and Javier Mascherano both likely to leave the club at the end of the current season.