| Iona (2) | | - | Russian, Georgian, Biblical Latin | |
| Iosif | | ee-O-seef (Russian), YO-seef (Romanian) | Russian, Romanian, Greek | |
| Ipati | | - | Russian (Rare) | |
| Ipatiy | | - | Russian (Rare) | |
| Ippolit | | - | Russian | |
| Ira (2) | | - | Russian | |
| Irakliy | | - | Russian | |
| Irina | | ee-REE-nah (Russian), EE-ree-nah (Finnish) | Russian, Bulgarian, Macedonian, Romanian, Finnish, Georgian | |
| Irinei | | - | Russian | |
| Iriney | | - | Russian | |
| Irinushka | | - | Russian | |
| Isaak | | ee-SAH-ahk (Russian) | Russian, German, Biblical Greek | |
| Isay | | - | Russian | |
| Isidor | | EE-see-dawr (German) | German, Russian, Macedonian | |
| Isidora | | ee-see-DHO-rah (Spanish), ee-zee-DO-rah (Italian), iz-i-DAWR-ə (English) | Serbian, Macedonian, Spanish, Portuguese, Russian (Rare), Italian (Rare), English (Rare), Ancient Gr | |