Erin's name day is observed on September 4 in the USA and on November 7 in Finland.
Erin is a globally recognized name that reached high popularity in the United States during the late 20th century. Derived from the Gaelic word for Ireland, its origin reflects a strong connection to the land and historical poetic traditions. The name is predominantly feminine and carries a mood characterized by natural beauty, soft elegance, and approachable strength. Across the world, it remains a classic choice in many English-speaking countries, maintaining its status as a timeless and melodic option. Its history is rooted in the Celtic Revival, making it a bridge between ancient heritage and modern naming styles. As a name, it conveys a sense of identity that is both specific to its roots and universal in its appeal.
| Country | Day | Month | Names |
 Austria | 8 | January | Erhard, Gudula, Severin |
 Croatia | 8 | January | Severin, Bogoljub, Apolinarij |
 Slovakia | 8 | January | Severín |
 USA | 8 | January | Alvis, Elvis, Severin, Severina, Severne |
 Lithuania | 23 | February | Butvile, Gantautas, Romana, Severinas |
 France | 24 | March | Catherine, Karine |
 Italy | 25 | March | Caterina di Svezia |
| France | 29 | April | Catherine |
| Italy | 29 | April | Caterina da Siena |
 Greece | 2 | May | Avgerinos, Matrona |
| Italy | 24 | May | Vincenzo di Lerins |
| USA | 16 | August | Craig, Kraig, Roch, Rochelle, Rochester, Rock, Rocky, Serena, Serenity, Serina |
| Lithuania | 20 | August | Bernardas, Neringa, Tolvinas |
 Spain | 26 | August | Ceferino |
 Bulgaria | 17 | September | Lyuba, Lyuben, Lyubomir, Lyubov, Nadezhda, Nadya, Sevda, Sofiya, Sofia, Vera, Vyara, Viara, Verin, Veradin, Vyara, Dragan, Drago, Dragoi, Dragomir, Nada, Lubomir, Lubomira |
 Latvia | 21 | October | Garlibs, Ginta, Gints, Severins, Urzula |
| Lithuania | 22 | October | Aliodija, Mingede, Severinas, Viltaras |
| Austria | 23 | October | Johannes, Severin, Uta |
| Croatia | 23 | October | Ivan Kapistran, Borislav, Severin |
 Germany | 23 | October | Severin |
| Latvia | 23 | October | Daina, Dainis, Severins |
 Norway | 23 | October | Severin, Søren |
 Sweden | 23 | October | Severin, Sören |
| Lithuania | 8 | November | Domante, Gotfridas, Severinas, Svirbutas |
| Bulgaria | 24 | November | Ekaterina, Katerina, Katina, Katya, Iasna, Yasna, Tinka |
 Ukraine | 24 | November | Katherine, Katerina |
 Czechia | 25 | November | Kateřina |
| France | 25 | November | Catherine |
| Greece | 25 | November | Merkourios, Katerina, Catherine, Karen |
| Italy | 25 | November | Caterina d'Alessandria |
 Romania | 25 | November | Ecaterina |
| USA | 25 | November | Caitlin, Caitlyn, Carina, Caryn, Catherine, Cathleen, Cathy, Kaitlin, Kaitlynn, Kara, Karen, Kari, Karina, Kate, Katelyn, Katelynn, Katharine, Katherine, Kathleen, Kathryn, Kathy, Katie, Katrina, Treena, Trina, Trinity |
| Croatia | 27 | November | Virgilije, Severin, Velimir |
| France | 27 | November | Séverin |
 Russia | 7 | December | Ekaterina |
| Latvia | 28 | December | Inga, Ivita, Jonatans, Mierins |
Finland