Side Lights

What Are Marine Side Lights?

Marine side lights are among the most critical components of any vessel's navigation lighting system. These red and green lights are mounted on the port (left) and starboard (right) sides of a boat, and they serve a purpose far beyond simple visibility — they communicate your vessel's heading and direction to every other mariner on the water. A red light on the port side and a green light on the starboard side allow approaching boats to instantly determine your vessel's orientation and take appropriate action to avoid a collision.

Why Side Lights Matter

Navigation lighting isn't optional — it's the law. Vessels are required to display proper navigation lights from sunset to sunrise and during any period of reduced visibility, such as fog or heavy rain. As the responsible party, the vessel owner and operator are legally accountable for ensuring the correct lights are displayed at all times while underway.

Port sidelights are red and starboard sidelights are green, and both shine from dead ahead to 112.5° aft on either side. Together with a stern light, the sidelights create a full 360° circle of visibility around the vessel, making your position and direction readable from every angle. For powered boats under 12 meters (39.4 feet), sidelights must be visible for at least 1 nautical mile. Larger vessels require 2-nautical-mile visibility.

Choosing the Right Side Lights for Your Vessel

Not all side lights are interchangeable. The correct choice depends on your vessel's length, type, and the waters you navigate. Key considerations include:

• Boat size: Requirements differ for vessels under 12m, 12–20m, and those over 20m in length.
• Mounting style: Flush deck-mount, surface-mount, and combination bi-color bow light styles are all available depending on hull design.
• Light technology: LED side lights are increasingly favored for their brightness, energy efficiency, and long service life — important advantages on overnight passages or extended voyages.
• Housing material: Stainless steel, chrome-plated brass, and high-impact plastic options offer varying levels of durability and corrosion resistance for fresh and saltwater environments.
• Regulatory compliance: Always verify that the lights you choose meet USCG, ABYC A-16, and any applicable CE standards for your vessel class.

Top Brands in Marine Side Lights

Seachoice is a well-known name among fishing, boating, and watersports enthusiasts, offering a broad range of marine accessories and OEM replacement parts manufactured to rigorous standards. Their side light lineup includes flush-mount stainless steel and chrome/brass housings designed to meet both CE and USCG requirements, with options for vessels under 39 feet up to larger cruisers.

Attwood Marine is widely regarded as one of the marine industry's most trusted navigation light manufacturers. Their LightArmor series of side lights features proprietary modular LED light engine technology, IP67-rated water and dust resistance, and stainless steel construction — meeting ABYC C-5, A-16, and USCG CFR 183.81 standards for vessels up to 65.6 feet. With an extensive catalog spanning deck-mount, portable, and pole-mounted designs, Attwood offers a solution for virtually every vessel type and size.