The Jones Act and Puerto Rico: What It Is and Why It Matters for Shipping

For companies shipping freight to Puerto Rico and for businesses operating on the island, a clear understanding of the Jones Act is essential. In this article, we define the Jones Act, explain why it exists, and outline the role it plays in shaping the Puerto Rico trade.

The Jones Act is part of the Merchant Marine Act of 1920, a federal law enacted to strengthen the United States maritime industry following World War I.

At its core, the Jones Act governs domestic ocean shipping between U.S. ports. It requires that cargo transported between U.S. ports be carried on vessels that are:

• U.S.-Flagged
• U.S.-Built
• U.S.-Owned
• U.S.-Crewed

Another term often used to describe this is “coastwise trade.”

In practical terms, if cargo is moving from Jacksonville, Fla., to San Juan, Puerto Rico, or from Houston, Texas, to Puerto Rico it must travel on a qualified Jones Act vessel.

The Merchant Marine Act of 1920 was created to ensure that the United States maintains:

• A strong domestic maritime industry
• A fleet of vessels available for national defense
• A base of trained American mariners
• Reliable domestic shipping infrastructure

The law was designed not only for economic stability but also for national security. A robust U.S.-flag fleet ensures the country has ships and skilled crews available during times of war, emergency, or natural disaster.

Today, the Jones Act applies to all domestic waterborne trade between U.S. ports including Alaska, Hawaii, Guam, and Puerto Rico.

Puerto Rico is a U.S. territory. As such, shipments between the mainland United States and Puerto Rico are considered domestic commerce, not international trade.

That distinction is critical.

Shipping from Miami to the Dominican Republic can be handled by a foreign-flag vessel. Shipping from Jacksonville to San Juan must move on a Jones Act carrier.

Because Puerto Rico relies heavily on ocean freight for essential goods including food, medicine, fuel, construction materials, and retail inventory, the Jones Act plays a central role in the island’s supply chain.

Foreign-flag vessels operate under the laws and labor standards of their flag state. They often crew ships with multinational labor and operate under different regulatory and safety frameworks.

Jones Act carriers, by contrast:

• Operate under U.S. Coast Guard oversight
• Comply with U.S. labor laws
• Employ American mariners
• Invest in U.S.-built vessels and infrastructure

While foreign carriers can and do serve Puerto Rico in international lanes (for example, from Europe or Latin America), they cannot transport cargo between U.S. ports.

Much of the discussion around the Jones Act focuses on cost. But in Puerto Rico, the more strategic conversation around the Jones Act is how it supports resiliency for the island.

Jones Act carriers serving Puerto Rico operate dedicated trade lanes with fixed, frequent sailings. This provides predictable capacity between the mainland and the island.

In markets dependent on global carriers, capacity can shift based on international demand cycles. In the Puerto Rico trade, Jones Act carriers are committed to serving the lane, which supports greater rate stability over time.

Because Puerto Rico is treated as domestic trade, cargo is not subject to international customs delays when moving from the mainland. That domestic designation supports streamlined documentation and more consistent transit planning.

In times of global shipping disruption, Puerto Rico’s domestic ocean shipping network provides insulation from international volatility.

Jones Act carriers have invested billions in vessels, terminals, and port infrastructure serving Puerto Rico.

These are not opportunistic deployments based on short-term rate swings. They represent long-term commitments to the trade, including modern vessels, LNG-powered ships, specialized equipment, and dedicated terminal operations.

The Jones Act fleet has played a crucial role in hurricane response and disaster recovery across Puerto Rico.

Because carriers maintain dedicated assets in the trade, they can rapidly restore service following storms. U.S.-based crews and companies are positioned to coordinate closely with federal and local agencies during recovery efforts.

This is perhaps the most common question surrounding the Jones Act within the Puerto Rico trade.

There is a persistent perception that the law drives significantly higher costs. However, the cost discussion often overlooks broader value considerations.

As discussed in industry forums, including recent conversations featuring Trailer Bridge leadership, freight cost is only one component of total landed cost and supply chain risk.

• Dedicated capacity reduces volatility
• Domestic regulatory frameworks reduce compliance complexity
• Long-term infrastructure investment reduces service disruption
• Reliable hurricane response reduces downtime

When evaluated purely on per-container ocean rates, comparisons can oversimplify the full economic picture.

For Puerto Rico, an island dependent on maritime trade, the value of continuity, predictability, and resilience must be part of the equation.

Nearly every category of commercial freight moves via ocean freight to Puerto Rico under the Jones Act. Because the island depends heavily on domestic ocean shipping, the variety of goods transported each week reflects the full spectrum of the Puerto Rican economy.

Common cargo shipped to Puerto Rico includes:

• Food and beverages
• Pharmaceuticals and medical supplies
• Retail goods and consumer products
• Construction materials
• Industrial equipment
• Automotive freight
• Fuel and energy-related cargo

In addition to standard containerized freight, ocean freight to Puerto Rico often includes oversized and specialized cargo such as heavy equipment, project freight, and over-dimensional machinery that supports infrastructure and industrial development across the island.

For shippers moving freight to Puerto Rico, the key is working with a Jones Act carrier that can handle diverse cargo requirements across the full domestic ocean shipping network.

Trailer Bridge’s asset-based model, including roll-on, roll-off and load-on, load-off barge service, allows customers to move everything from refrigerated consumer goods to oversized industrial cargo through a single Caribbean shipping partner.

The Jones Act has governed domestic ocean shipping for more than a century. In the Puerto Rico trade, it provides structure, stability, and long-term investment.

For businesses shipping to Puerto Rico, the conversation is not simply about compliance. It is about selecting the right partner within a regulated domestic framework. One that offers reliability, capacity, operational scale, and strategic coordination to keep their supply chain moving.

As Puerto Rico continues to strengthen its island infrastructure and manufacturing sectors, Jones Act carriers will remain a key supporter of economic growth and supply chain continuity across the island.