Alagoas was a destroyer of the Brazilian Navy, serving from 1909 to 1939. She was named after the Brazilian state of Alagoas.
The ship had an overall length of , a beam of and a draught of . She was powered by 2 triple expansion reciprocating steam engines, driving two shafts, which developed a total of and gave a maximum design speed of . During the trials the contract speed was exceeded, and the vessel was clocked at . Steam for the turbines was provided by two double-ended Yarrow boilers. Alagoas carried a maximum of of coal that gave her a range of approximately at .
The ship mounted two guns in single mounts. In addition, four 47 mm (3pdr) cannons in single mounts were deployed at the time of launching.
The official full speed trial for Alagoas took place on November 26, 1909 on the Skelmorlie deep-water measured mile at the mouth of the Clyde. During a continuous three hour run with a 100 ton load, the ship exceeded her contract speed of 27 knots.