- Iđni = He who works a lot.
- Ifill = A falcon. A name that suits grey horses particularly well, as do the next two names. Valgrá is one of the mares' names with a similar meaning.
- Ifjungur = A falcon.
- Ifli = A falcon.
- Ígull = Sea-urchin, hedgehog.
- Illingur = A bad animal. This was the name of the horse owned by Ţorgrímur from Trađarholt in Flói: "This was a horse of little quality" (Flóamanna saga). The surname illingur seems to mean a bad person.
- Ímaldur = Old and uncommon mn.
- Ímar = Grey with rime or grey with hoar-frost, or white or black ring around the eyes. Name of a wolf.
- Ími = Old and uncommon mn. Name of a wolf. Suggests a rime-covered look.
- Ímir = The rime-grey animal. Name of a wolf.
- Ímnir = A sword.
- Inni-Krákur = It says in the Fljótsdćla saga that Gróa from Eyvindará "had not been a farmer for long, before she raised one animal among her live-stock which she considered better than her other possessions of equal quality. This was a horse, which she called Inni-Krákur, because it was kept indoors every winter. It was black. She had it castrated early." (look at Krákur).
- Íringur = look at Ýringur.
- Ísak = Isaac, a Biblical name.
- Ísungur = Head cloth.
- Ívaldi = Old and common mn.
- Ívan = Ivan, a Russian name.
- Ívi = Archer; name of a sea-lord.