Carrier tariffs are publicly filed schedules of rates, rules, and terms that a transportation or telecommunications company must apply equally to every customer. When a tariff is on file with a federal agency, the price printed in that document is the only legal price the carrier can charge, and the terms in that document are the terms you are legally presumed to have agreed to, whether or not you ever read them. That cuts both ways: a carrier cannot quietly bill you more than the tariff allows, and you cannot enforce a verbal discount below it.
The stakes are practical. Knowing what a tariff contains, which agency polices it, and how long you have to dispute a charge can be the difference between recovering an overcharge and losing the right to challenge it.
What Is Inside a Carrier Tariff
A tariff lays out every charge a customer could face. Base rates come first, then surcharges tied to variable costs such as fuel, port congestion, or environmental compliance. Ocean freight tariffs, for instance, publish a per-container rate and then apply fuel-related adjustments that move with the market.
Accessorial fees cover services outside the standard scope: liftgate delivery when the destination has no loading dock, redelivery when no one is available to accept the shipment, inside delivery when freight has to come into a building rather than sit at the curb. Demurrage and detention are the two accessorials that catch shippers most often. Demurrage applies when a container sits at a marine terminal past its free time; detention applies when you hold a carrier’s equipment past pickup. Rates vary by carrier, port, and terminal, and the Federal Maritime Commission has noted that carriers use these terms differently, which makes direct comparisons difficult.
Service classifications separate tiers of speed or handling. A rail tariff, for example, may treat standard and expedited freight as separate rate structures. Geographic routing rules identify which rates apply to which origin-destination pairs and weight classes.
Liability limits sit inside the terms and conditions and often surprise shippers. Under the Carriage of Goods by Sea Act, ocean carrier liability is capped at $500 per package or per customary freight unit unless you declare a higher value before shipment and note it on the bill of lading.1Office of the Law Revision Counsel. 46 U.S. Code 30701 – Carriage of Goods by Sea Act That figure dates to 1936 and has never been adjusted for inflation. You and the carrier can agree in writing to a higher ceiling; you cannot agree to a lower one.
Why the Filed Rate Binds Both Sides
The filed rate doctrine requires any carrier that files tariffs with a federal agency to charge exactly the rates in those filings. The Supreme Court reinforced this in Maislin Industries, U.S., Inc. v. Primary Steel, Inc., holding that “the filed rate doctrine forbids as discriminatory the secret negotiation and collection of rates lower than the filed rate.”2Legal Information Institute. Maislin Industries, U.S. v. Primary Steel, 497 U.S. 116 (1990) The practical result: any handshake deal that contradicts the filed tariff is legally unenforceable.
The law also treats a filed tariff as constructive notice. You are legally presumed to know its terms. That presumption works for you as well as against you — you can hold the carrier to its published rate as firmly as the carrier can hold you to it.
Deadlines to Dispute an Overcharge
Federal telecommunications law gives you two years from the date of an overcharge to file a complaint with the FCC or sue. Sending the carrier a written claim within that first two-year period buys you another two years running from the date the carrier denies the claim.3Office of the Law Revision Counsel. 47 U.S. Code 415 – Limitations of Actions Miss those deadlines and the right to recover disappears.
Notice Before Rates Change
Carriers cannot change tariff rates without warning. FCC rules require advance public notice, with the lead time keyed to the type of filing. Rate decreases under streamlined filings need 7 days’ notice; rate increases or changes to terms need 15 days; non-price-cap local carriers proposing rate increases or new service offerings must give 45 days; the default for filings not covered by a specific rule is 35 days.4eCFR. 47 CFR 61.58 – Notice Requirements The notice window is also your window to petition against the change before it takes effect.
Which Agency Regulates Which Carrier
Federal Communications Commission
The FCC handles tariff filings for interstate wireline telecommunications. Filings go in through the FCC’s electronic system and are open for public inspection.5eCFR. 47 CFR Part 61 Subpart B – Rules for Electronic Filing A carrier that fails to comply with its tariff filing obligations faces a $6,000 penalty per offense plus $300 for each day the violation continues, and charging anything other than the filed rate — whether the deviation is an overcharge, a secret discount, or a rebate — is itself illegal under the Communications Act.6Office of the Law Revision Counsel. 47 U.S. Code 203 – Schedules of Charges
Federal Maritime Commission
The FMC oversees ocean common carriers and marine terminal operators, with a mission to protect the shipping public from unfair and deceptive practices.7Federal Maritime Commission. Ocean Transportation Intermediaries Under the Shipping Act, every common carrier must keep its rates in an automated tariff system open to public inspection, with exceptions for certain commodities including bulk cargo, forest products, recycled metal scrap, new assembled motor vehicles, and waste paper.8Office of the Law Revision Counsel. 46 U.S. Code 40501 – General Rate and Tariff Requirements The FMC is required to publish all penalties assessed against carriers on its website.
Surface Transportation Board
The STB handles economic regulation of freight rail.9Surface Transportation Board. Legal Resources Rail carriers must set reasonable rates and provide them in writing or electronically to anyone who asks.10Office of the Law Revision Counsel. 49 U.S. Code 11101 – Rail Carrier Providing Transportation A carrier cannot raise common carrier rates without 20 days’ written or electronic notice to anyone who has requested rates or arranged a shipment in the prior 12 months. STB penalties are steep: in 2026, overcharging or undercharging a tariff rate carries an adjusted penalty of $204,862 per violation, and other tariff-related violations run $1,025 for a first offense and $4,097 for each subsequent one.11Federal Register. Civil Monetary Penalties-2026 Adjustment
When a Tariff No Longer Applies
Not every carrier service still operates under a filed tariff. The FCC has removed tariff requirements from large categories of telecommunications through a process called detariffing, on the theory that competition can discipline prices where the market is open. The main milestones:
- Domestic long-distance (May 2000): non-dominant carriers required to cancel interstate interexchange service tariffs.
- International long-distance (January 2002): non-dominant carriers canceled international interexchange tariffs and may not file new ones.
- Business data services (August 2020): price cap carriers and competitive local exchange carriers detariffed packet-based data services, high-capacity transport, and many end user channel termination services. Rate-of-return carriers electing incentive regulation must detariff qualifying services within 36 months of that election.
Services that still require tariffs are primarily those offered by dominant local exchange carriers in areas where competition has not been deemed sufficient.12Federal Communications Commission. Tariffs If your service is detariffed, your rights come from the carrier’s contract or terms of service. The filed rate doctrine does not apply and the FCC complaint deadlines above are not your reference point.
Ocean shipping has its own version. Carriers and shippers can negotiate confidential service contracts that commit the shipper to a minimum volume and the carrier to a specific rate and service level. These contracts must be filed with the FMC within 30 days of taking effect but are not published as tariffs.13eCFR. 46 CFR Part 530 – Service Contracts If the FMC prohibits or suspends a service contract, shipments made under it get re-rated at the carrier’s published tariff.
Demurrage and Detention Billing Rules
The Ocean Shipping Reform Act of 2022 changed how carriers can bill for demurrage and detention. Every invoice must now include at least 13 specific items, among them the container number, the dates free time starts and ends, the applicable daily rate, the total amount due, and contact information for disputing the charge. The invoice must also carry a statement that the carrier’s own performance did not cause or contribute to the charges.14Congress.gov. S.3580 – Ocean Shipping Reform Act of 2022 If an invoice omits any required item, the billed party has no obligation to pay it. A sloppy invoice is an unenforceable invoice.
The FMC’s implementing rule sets the timing. Carriers must issue demurrage and detention invoices within 30 calendar days, and if an invoice needs correction, the carrier gets another 30 days to send a corrected version. Billed parties must be given at least 30 days to request fee mitigation, refund, or waiver, and the carrier must attempt to resolve that request within 30 days.15Federal Register. Demurrage and Detention Billing Requirements The FMC publishes findings of false invoice information and penalties on its website, so you can check a carrier’s record before booking.
Challenging a Rate or Charge
Telecommunications
Before filing a formal complaint with the FCC you must first try to settle with the carrier, including executive-level discussions in business-to-business disputes. If that fails, the formal complaint goes through the FCC’s electronic system, the carrier has 30 days to respond, and you have 10 days after that to reply.16eCFR. 47 CFR Part 1 Subpart E – Complaints, Applications, Tariffs, and Reports Involving Common Carriers You can also petition to suspend or reject a new tariff filing before it takes effect, but the window is tight: from 3 calendar days for filings with 7 days’ notice up to 25 days for filings with 90 or more days’ notice. Miss it and the tariff goes into effect as filed.
Ocean Shipping
The FMC’s Office of Consumer Affairs and Dispute Resolution Services offers mediation, facilitation, arbitration, and ombuds assistance for cargo-related disputes at no cost. You submit form FMC-33 with supporting documentation.17Federal Maritime Commission. Consumer Affairs and Dispute Resolution Services For most shippers this is the right first step. It is faster and cheaper than formal litigation.
Freight Rail
Challenging a freight rail rate at the STB is the most involved path. You must show market dominance over the route and that the challenged rate is unreasonable. Under the Final Offer Rate Review procedure, both sides submit a proposed maximum rate, and if the Board finds the existing rate unreasonable, it picks one of the two offers as the new ceiling.18Federal Register. 19eCFR. 49 CFR Part 1111 – Complaint and Investigation Procedures
Where to Find a Tariff
For telecommunications, the FCC’s Electronic Tariff Filing System is the starting point. You can search by carrier name or filing number to see current and historical rate structures.20Federal Communications Commission. Electronic Tariff Filing System Because many telecom services have been detariffed, ETFS will not have filings for services like long-distance from non-dominant carriers.
For ocean shipping, the FMC maintains a list of tariff locations and carrier information through its databases, including the SERVCON system for service contract filings.21Federal Maritime Commission. Databases and Publications Individual service contracts are confidential, but each carrier’s automated tariff rates must be publicly available, and most ocean carriers host them on their corporate websites under a link labeled “Tariffs” or “Public Filings.”
Rail tariffs are accessible through the individual websites of the major rail carriers, usually through a search tool where you input origin and destination. If you cannot find one online, request it from the carrier in writing. The carrier is legally obligated to respond promptly.10Office of the Law Revision Counsel. 49 U.S. Code 11101 – Rail Carrier Providing Transportation