Swimming at the 2018 Mediterranean Games – Women's 400 metre individual medley

The women's 400 metre individual medley competition at the 2018 Mediterranean Games was held on 23 June 2018 at the Campclar Aquatic Center.

Records
Prior to this competition, the existing world and Mediterranean Games records were as follows:

The following records were established during the competition:

Heats
The heats were held at 10:31.

Final
The final was held at 18:44.