Lagoa de Itaipu is a coastal lagoon located in the Região Oceânica of Niterói, in the state of Rio de Janeiro, Brazil, at approximately 22°57′28.1″S, 43°02′35.9″W. The lagoon covers approximately 1,470,000 square meters of navigable water, making it a reasonably sized body suitable for small boats, launches, and paddlecraft. It connects to the sea via the Itaipu Canal, which links the lagoon's waters to the adjacent ocean.

For paddlers, the canal connecting the lagoon to the sea offers calmer conditions well suited to stand-up paddleboarding and beginner-level surf paddling. The lagoon itself is appropriate for small craft navigation throughout its navigable extent. Weekday mornings tend to see fewer visitors, which translates to a quieter experience on the water with less boat traffic to contend with.

The lagoon supports a diverse range of fish species, including Northern red snapper, Atlantic croaker, ocean triggerfish, common snook, crevalle jack, silver scabbardfish, and bluefish. This variety reflects the lagoon's connectivity to both brackish and marine environments via the canal, and paddlers are likely to encounter active fishing activity on the water.

The surrounding area includes Morro das Andorinhas and is in proximity to Praia de Itaipu and Praia de Camboinhas. Nearby Praia de Piratininga and the larger Lagoa de Piratininga (approximately 4,130,000 square meters) are also accessible in the broader Região Oceânica, offering potential for extended paddling exploration in the area. The region sits within Niterói, which features a City Park designated as an environmentally protected area, with panoramic views toward Guanabara Bay and the Tijuca National Park visible from elevated points nearby.