What it is

Cover 3 is a zone defense where three defenders, usually the two corners and the free safety, each take a deep third of the field, and four others cover the short zones.

In a game

It is strong against deep passes and balanced against the run. The weak spots are the flats and the seams between the thirds, which offenses attack with quick throws and routes that split the zones.

More detail

The three deep defenders split the field into thirds, and four others cover the short zones. In some versions the strong safety comes down to the flat, in others a corner does. It protects against deep passes but gives up the short areas, so quick throws and curl-flat combinations attack it.

Animated diagram

1. Two cornerbacks and a free safety drop deep and each guards one third of the field.
2. Four defenders cover the shorter zones underneath: two on the sides and two in the middle.
3. The offense attacks the seams between the zones and the gaps under the deep defenders.