Konstantin: Name day
Name Day List: Konstantin
| Country | Day | Month | Names |
 Bulgaria | 21 | May | Elena, Konstantin, Kosta, Kostadin, Kostadinka, Lenko, Dicho, Lenko, Dinko, Elenko, Eli, Elin, Elka, Ilona, Kojcho, Kostadina, Kostadinko, Kuncho, Stamen, Stanimir, Stanimira, Stanka, Stoil, Stoyan, Stoian, Stoyanka, Trayko, Dinko |
 Estonia | 21 | May | Konstantin, Kostel, Tiino, Kindel |
 Finland | 21 | May | Konsta, Kosti, Konstantin |
 Hungary | 21 | May | Konstantin |
 Sweden | 21 | May | Conny, Konstantin |
Name Day List - similar names (Konstantin)
Latvia 
Lithuania 
Greece 
Slovakia