With Venezia FC having just been promoted to Serie A for next season, this is possibly the final opportunity to visit a stadium which is only accessible by Vaporetto or on foot. That's right, it's on an island, so I assume the "foot" bit is over a bridge(s).
Anyhow, the Stadio Pier Luigi Penzo, the second oldest in Italy, is basically one old stand and three temporary stands, with a capacity of 11k or 7.5k, depending on which source you believe:
Stadio Pier Luigi Penzo – StadiumDB.com
Meanwhile, they've announced plans to move to a new 18.5k stadium on the mainland, possibly from some time in 2027, though knowing Italian bureaucracy, that may be being optimistic:
Italy: Venezia FC prepares for new stadium construction