Immediately after commissioning, "Maratanza" saw service in support of General George B. McClellan's Peninsula Campaign, operating on the York and James rivers from April to September 1862. After participating in the capture of Yorktown on 3 May 1862, "Maratanza" shelled various points, including Wormley's Creek, Murrell's Inlet, and Fort Darling (Drewry's Bluff). En route to scouting Turkey Bend on 4 July 1862, she engaged and captured the Confederate steamer CSS "Teaser" at Haxall's.