Isla's name day is observed on September 14 in Finland.
The name Isla is a distinctly feminine name whose origin relates directly to the geographical term for "island." Historically, the name was long established in Scotland but only recently achieved massive popularity in the United States, entering the Top 100 in the 21st century. It conveys a sophisticated and elegant mood, characterized by a soft and charming personality. Due to its smooth pronunciation and nature-like derivation, Isla appeals widely to modern parents. It is universally classified as a female identifier, avoiding any unisex application globally.
| Country | Day | Month | Names |
 Croatia | 4 | January | Sdislava |
 Bulgaria | 6 | January | Bogomil, Bogdan, Bogdana, Bozhidar, Bozhidara, Borislav, Borislava, Jordan, Yordan, Yordanka, Nayden, Teodosii |
| Croatia | 7 | January | Rajmund, Lucijan, Zorislav |
 Czechia | 10 | January | Břetislav |
 Norway | 13 | January | Gislaug, Gisle |
 Slovakia | 13 | January | Rastislav |
| Croatia | 16 | January | Marcel, Oton, Mislav |
| Czechia | 18 | January | Vladislav |
| Croatia | 27 | January | Angela, Vitalijan, Pribislav |
| Croatia | 28 | January | Toma, Tomislav |
| Czechia | 29 | January | Zdislava |
| Croatia | 7 | February | Pio, Rikard, Držislav |
| Slovakia | 10 | March | Branislav, Bruno |
| Croatia | 12 | March | Bernard, Budislav, Maksimilijan |
| Croatia | 20 | March | Klaudija, Dionizije, Vladislav |
 Austria | 11 | April | Hildebrand, Stanislaus |
| Croatia | 11 | April | Stanislav, Stana, Radmila |
 France | 11 | April | Stanislas |
 Italy | 11 | April | Stanislao |
 Spain | 11 | April | Gema, Oria, Estanislao |
| Bulgaria | 12 | April | Vencislav, Vencislava, Violeta, Varban, Girgin, Girgina, Dilyan, Dilyana, Zdravka, Zdravko, Latinka, Lilyana, Margarita, Nevena, Roza, Rosen, Rosica, Trendafil, Trendafilka, Tsvetan, Tsveta, Tsvetanka, Tsviatko, Tseno, Stanislav, Stanislava |
| Croatia | 19 | April | Konrad, Ema, Rastislav |
| Czechia | 19 | April | Rostislav |
| Bulgaria | 26 | April | Toma, Tomislav, Tomislava |
| Czechia | 28 | April | Vlastislav |
| Bulgaria | 2 | May | Boriana, Boris, Borislav, Borislava, Boryana, Zhivko, Zhivka, Zhivodan |
| Czechia | 7 | May | Stanislav |
 Denmark | 8 | May | Stanislaus |
 Latvia | 8 | May | Aiga, Ceronis, Inita, Stanislavs, Stefanija |
| Czechia | 9 | June | Stanislava |
| Slovakia | 9 | June | Stanislava |
| Bulgaria | 17 | June | Asparuh, Krum, Asen, Chavdar, Rumiana, Rumen, Momchil, Desislava |
| Slovakia | 18 | June | Vratislav, Vratislava |
| Bulgaria | 24 | June | Encho, Enyo, Yanka, Yanko, Yancho, Yanaki, Yani, Yanislav |
| Croatia | 27 | June | Ladislav kralj, Ciril Aleksandrijski |
| Czechia | 27 | June | Ladislav |
| Slovakia | 27 | June | Ladislav, Ladislava |
| Spain | 27 | June | Socorro, Zoilo, Ladislao, Anecto, Sansón |
| Bulgaria | 29 | June | Apostol, Kamen, Pavel, Pavlin, Pavlina, Pejo, Penka, Pencho, Petrana, Petar, Petya, Petzo, Petar, Petya, Pavel, Pavlina, Polina, Kamen, Asen, Asya, Desislava, Krym, Rumen, Rumyana, Chavdar, Asen, Asya, Desislava, Krum |
| Croatia | 3 | July | Toma apostol, Tomislav, Tomo, Miki |
| Croatia | 12 | July | Mislav, Tanja, Suzana |
| Austria | 29 | July | Ladislaus, Martha, Olaf |
| Latvia | 8 | August | Gotlibs, Mudite, Vladislavs |
| Croatia | 22 | August | BD Marija Kraljica, Regina, Vladislava |
| Latvia | 26 | August | Bronislava, Bronislavs, Glauda, Natalija, Nate |
| Croatia | 1 | September | Egidije, Branimir, Branislav |
| Czechia | 3 | September | Bronislav |
| Slovakia | 25 | September | Vladislav |
| Bulgaria | 6 | October | Toma, Tomislav, Tomislava |
| France | 10 | October | Ghislain, Virgile |
| Croatia | 23 | October | Ivan Kapistran, Borislav, Severin |
| Croatia | 1 | November | Svetislav, Sveto |
| Croatia | 8 | November | Gracija Kotorski, Milotislav, Bogdan |
| Austria | 13 | November | Eugen, Livia, Stanislaus |
| Croatia | 13 | November | Stanislav Kostka, Brcko b., Stanko |
| Slovakia | 13 | November | Stanislav |
 Finland | 28 | November | Heini, Kaisla |
| Bulgaria | 5 | December | Elisaveta, Sava, Savka, Svetoslav, Svetoslava, Slavi, Slavcho, Sabi, Savina, Stanislav |
| Czechia | 9 | December | Vratislav |
| Slovakia | 14 | December | Branislava |
| Bulgaria | 27 | December | Venci, Vencislav, Vencislava, Zapryan, Sonya, Stamen, Stanimir, Stanka, Stefan, Stefana, Stefaniya, Stefka, Stoil, Stoimen, Stoichko, Stojko, Stoyan, Stoyanka, Tanya, Tsanka, Tsanko, Tsonka, Tsonyu |