Marine services are port-related activities conducted to ensure the safe and expeditious flow of vessel traffic in port approaches and harbors and a safe stay at berth when moored or at anchor.

Marine services provide repair, maintenance, logistics, testing, storage, and transportation services for boats, ships, oil tankers, and another watercraft. Marine repair services and marine maintenance services usually have facilities at boatyards, shipyards, and marinas. They perform on-water repairs and drydock maintenance, and can overhaul or upgrade boats and ships. Marine logistics services include freight haulers and freight forwarding agencies, as well as companies that provide logistical support to the offshore oil and gas industry. Marine storage services usually have steel boat racks and dry stack storage buildings. Marine transportation services and other marine services are also commonly available.