Cruise Ship Visits Limited by Emissions Requirements, Market Demand

The biggest factor determining whether a cruise ship stops in San Francisco isn’t its size or passenger capacity, but its emissions. The California Air Resources Board (CARB) requires vessels to plug into shore power systems that limit pollution while they’re at berth. Not all ships are equipped to connect to shore power, with limited alternative docking locations and exemptions.

Cruise ships historically ran their auxiliary engines while docked to power lighting, air conditioning, kitchens, and other onboard systems. Those engines burn marine fuel and produce nitrogen oxides and particulate matter, which can affect air quality in surrounding neighborhoods. To address the issue, in 2007 California adopted regulations that require vessels to reduce emissions while at berth. One of the most common solutions is shore power, which allows ships to plug into landside electrical systems rather than running their engines.

Under the State of California’s Ocean-Going Vessels at Berth Regulation, each ship visit to a regulated California port or marine terminal must use a CARB Approved Emission Control Strategy (CAECS) to limit releases, unless the stopover qualifies for an exception or an alternative compliance option is used, according to Eric Young, Port of San Francisco director of communications.

If a ship can meet emission requirements it can dock at Pier 27, which serves as the City’s primary cruise terminal, designed to accommodate large vessels with modern shore power connections. After docking, crews attach high-voltage cables that supply electricity to the vessel from the electrical grid to enable onboard systems to continue operating without running engines. 

If it can’t meet emission requirements, the ship must dock at Piers 35 or 80, which don’t have a CAECS. Ships do so under the “Low Activity Terminal Exemption to the Rules,” which allows Piers 35 and 80 to accept no more than 19 non-CAECS vessels per year.

Outside of emission requirements, there’s no mandated limit on the number of cruise ships that may dock at City ports. The total depends on market demand and availability. In 2025, municipal ports hosted 91 vessels: 80 at Pier 27, four at Pier 35, and seven at Pier 80, a new port record, according to Young. Also, the Port of San Francisco hosted 34 unique cruise vessels – which offer specialized, curated, often intimate travel experiences – a new record from the previous high of 28 in 2024. All told, in 2025, there were approximately 373,000 passengers aboard those cruise ships. 

The City serves as a gateway for voyages to Alaska. Many ships sail under the Golden Gate Bridge before heading north along the coast, which creates a memorable passenger experience.

In addition to the record high of hosting vessels, four maiden calls – the first time a specific cruise ship visits a particular port – originated at City ports in 2025: Carnival Legend, Norwegian Jade, AIDA Cruises AIDAdiva, and Villa Vie Odessey 

“May 2025 was the highest single monthly passenger count at 49,201, overtaking 48,885 passengers in September 2024,” Young said. “Traditionally, the busiest cruise periods in San Francisco are in the spring and fall, with fall being the highest and spring slightly lower.”

In 2026, 89 calls have so far been scheduled; 2027 has 87; 2028 has 74. The Princess cruise line is the Port’s main customer. It has 45 scheduled calls this year; the Ruby Princess has 33 “homeport calls,” or the primary base of operations where the cruise begins and ends. The Port’s second largest customer is Carnival Cruises, with 22 scheduled homeport calls.   

As cruise lines upgrade their fleets with cleaner technologies and shore-power capability, more vessels are expected to meet California’s emissions standards.