Section 3: Playing Area
- Course: the racecourse is laid out with a start/finish area, one or more turn buoys, and guidance buoys marking the swim line, as shown in the course diagram at Appendix 1 of Part Three. The course must be in water subject to only minor currents or tide and may be salt or fresh water (Article 13.1.2.1 / Appendix 1 notes of Part Three).
- Turn buoys and guidance buoys: turn buoys marking alterations of the course are large inflatable markers roughly 3.00 m across and are a different colour to guidance buoys so Athletes can distinguish them (Article 12.1.4.1 of Part Three, Appendix 3 diagram); smaller guidance buoys of roughly 0.55 m line the course between turns to help Athletes hold the racing line (Appendix 1, Appendix 3 of Part Three).
- Starting platform: at World Aquatics Events the starting platform length must be at least (number of Athletes x 0.60 m) plus five metres on each side, with Athlete start spaces 60 cm wide and numbered in ascending order (Articles 12.1.2.1–12.1.2.2 of Part Three).
- Feeding platform: sized on the same formula using the number of feeders in place of Athletes (Article 12.1.5.1 of Part Three); floating feeding platforms or stationary feeding stations must be available at least every 2.5 km in races greater than 5 km (Article 14.3.6 of Part Three).
- Finish: the finish apparatus is a vertical facing finish plate at least five metres wide, with its bottom edge no less than 500 mm and no greater than 700 mm above the waterline (Article 12.1.3.3 of Part Three); an Athlete finishes by touching the finish plate, or by crossing the finish line if no plate is used (Articles 5.3–5.4 of Part Three).
- Course depth: the minimum water depth at any point on the course must be 1.40 metres (Article 12.2.2 of Part Three).
- Water temperature: the water temperature must be a minimum of 16.0°C and a maximum of 31.0°C, checked at three points around the course at a depth of 40 cm two hours before the race by a commission of an appointed Referee, an LOC representative, and a team representative (Articles 12.2.3–12.2.3.3 of Part Three).
- Water quality: venue suitability is determined against WHO-aligned Enterococci and E. coli thresholds — for seas, oceans, and other tidal waters, "excellent" water quality is Enterococci <100 cfu/100mL and E. coli <250 cfu/100mL, rising through "good," "fair," and "unacceptable" bands with correspondingly higher counts; inland waterways use higher thresholds at each band (Articles 13.1.3.3–13.1.3.4 of Part Three). Organisers must submit water quality analysis reports two months, seven days, and no more than 48 hours before the competition, plus a sample on the day of competition (Article 13.1.4.1 of Part Three).