Five ships of the United States Navy have borne the name Alert. During World War I, three ships held the name simultaneously.
- USS Alert (1812), was an 18-gun sloop-of-war captured from the United Kingdom in the War of 1812 that was sold in 1829 for breaking up.
- USS Alert (1861), was a screw tug used during the Civil War.
- USS Alert (AS-4), was a screw steamer in use during the late 19th century and World War I.
- USS Alert (1896), was a steam launch acquired from the Coast Guard during World War I.
- USS Alert (SP-511), was used as a patrol boat during World War I.
Seven cutters of the United States Coast Guard have borne the name Alert.
- ^ Canney, p 11
- ^ Canney, p 13
- ^ Canney, p 45
- ^ Canney, p 59
- ^ Canney, p 62
- ^ Canney, p 98
- ^ Scheina, p 57
- ^ Scheina, p 40