The Ringvaart, formally known as the Ringvaart of the Haarlemmermeer Polder, is a circular canal in the province of North Holland, the Netherlands. It runs 61 kilometres in length and reaches a depth of 2.4 metres, enclosing an area of more than 180 square kilometres. As its name suggests, it forms a complete ring around the Haarlemmermeer polder and serves as the boundary of the Haarlemmermeer municipality.

Construction began in 1839 as the first phase of reclaiming land from the Haarlemmermeer, a large lake. Thousands of laborers dug the canal to follow the lake's contour as closely as possible, though at three locations — Vijfhuizen, Lisserbroek, and Huigsloot — the canal was cut through peninsulas that subsequently became part of the polder. The canal was completed in 1845 and used to drain the lake. This history gives the waterway considerable cultural and engineering significance, and the broader Haarlemmermeer reclamation project is recognized as a UNESCO World Heritage Site.

The Ringvaart carries both commercial and recreational boat traffic, so paddlers should be prepared to share the water with larger vessels. A portion of the canal forms part of a recognized sail route connecting Hollands Diep to the IJsselmeer, and this section is navigable by vessels with masts exceeding 6 metres. The presence of commercial traffic is an important safety consideration for anyone paddling on the canal.

Near Roelofarendsveen, the Ringvaart passes beneath the A4 motorway via a navigable aqueduct, the oldest in the Netherlands, originally built in 1961. In 2006, two additional aqueduct sections were completed — one for expanded northbound motorway lanes and one for the HSL-Zuid high-speed railway — bringing the total aqueduct length to 1.8 kilometres. Paddlers navigating this stretch will pass through this notable piece of infrastructure.

The canal supports a variety of fish species including European perch, Northern pike, and zander, which may be of interest to paddlers who also fish. The circular geometry of the canal makes it well suited to multi-day circumnavigation trips, with the full 61-kilometre loop offering a structured route through the flat polder landscape of North Holland.