Seydlitz participated in many of the large fleet actions during World War I, including the battles of Dogger Bank and Jutland in the North Sea. The ship suffered severe damage during both engagements; during the Battle of Dogger Bank, a 13.5 in (34.3 cm) shell from the British battlecruiser Lion struck Seydlitz's rearmost turret and nearly caused a magazine explosion that could have destroyed the ship. At the Battle of Jutland she was hit twenty-one times by large-caliber shells, one of which penetrated the working chamber of the aft superfiring turret.