A time-depth recorder was attached to a female Northern elephant seal at the end of her lactation fast before she entered the sea to feed. The animal dived continuously during its first 11 days at sea, the period recorded for a total of 653 dives. Mean dive time was 21 min, with the longest submersion lasting 32 min. Mean surface interval between dives was 3 min, resulting in a total surface time of 11 %. Mean dive depth was 333 m and the deepest dive was 630 m, the deepest ever recorded for a pinniped. A d̀epth histogram recorder attached to another female yielded a similar frequency distribution of dive depths.