How to Cross the Border: The San Ysidro & CBX Guide

People have been crossing between San Diego and Tijuana at San Ysidro since 1906, and the port has been growing ever since. The current facility dates to a 1973 build. Then came a federal expansion that ran from 2009 to 2019, cost roughly $625 million and produced the layout in use now, including 34 northbound vehicle lanes served by 62 booths. On a typical day, something like 70,000 vehicles and 20,000 people on foot head north through San Ysidro. It ranks among the busiest land border crossings on the planet.

For a walking day trip, the first decision is where you'll cross, and the answer is PedEast. It's the San Ysidro pedestrian crossing that sits right beside San Ysidro Transit Center, the final stop on the UC San Diego Blue Line, and the two share an address at 700 E San Ysidro Blvd. CBP lists PedEast as open 24 hours a day, with up to 22 pedestrian lanes split between standard processing and Ready Lane for the walk back north.

San Ysidro has a second pedestrian crossing, PedWest, and it's a nice bonus when it's running. Its current hours are 6 AM to 2 PM, and that window has changed several times since it reopened. When CBP's live wait page shows PedWest open on the day, it can be an option. For an evening return, a lunch that stretches into dinner, or any plan with a fixed time back on the U.S. side, PedEast is the crossing to build around.

Settling this first makes every later choice easier. Once PedEast is the plan, the trolley you ride down, the lane you choose coming home and the time you leave yourself on the far side all line up behind it. It's also why this decision sits at the top of the guide, ahead of the paperwork and the transit: every other step starts from the crossing point.

Cross Border Xpress, or CBX, solves one very specific problem, and it solves it well. It's a private terminal on Otay Pacific Drive in Otay Mesa with a bridge that carries passengers over the border and straight into Tijuana International Airport, better known as TIJ. Otay-Tijuana Venture, L.L.C. has run it since 2015, and it operates 24 hours a day, 365 days a year. If your trip starts or ends with a flight out of TIJ, this is your crossing.

It's built for fliers only, and the rules follow from that. Heading south, you need a CBX ticket plus a boarding pass for a TIJ departure within the next 24 hours. Heading north, your boarding pass has to show you landed within the last 2 hours, and you stay inside the secure baggage-claim area to reach the bridge. Without a TIJ boarding pass, the bridge is closed to you, so a walking day in Tijuana goes through PedEast instead.

The booking order matters. Lock in the flight first, then buy the bridge ticket more than 2 calendar days ahead. At regular-season prices checked in late July 2026, a one-way ticket started at $31.99 booked in advance and $37 at the last minute, and a round trip started at $51.99 in advance and $57 last-minute. High-season one-way fares start at $36.99.

Travelers who use the enclosed bridge tend to describe it as a convenient, comparatively quick way to reach the airport, especially when the ticket and parking are sorted ahead of time. The same travelers note that lines build at peak periods, and that it helps to confirm which queue is yours when several flights land or depart together. Arrive with time to spare and settle parking before the day, and the crossing stays easy.

One family note: an unaccompanied minor can't travel on a standard CBX ticket. CBX runs a separate Unaccompanied Teen Service for that situation.

Here's the part of the trip that happens at the kitchen table, and it decides whether the rest goes smoothly. Two countries check your documents on a Tijuana day trip, Mexico on the way in and the United States on the way back, and the paper that satisfies one side doesn't always cover the other. The cleanest answer for both directions is an unexpired passport book for every person going.

The U.S. side accepts a longer list for a return by land. CBP's current rules count the passport book, a passport card, an Enhanced Driver's License, a Trusted Traveler card from NEXUS, SENTRI or FAST, a military ID for someone traveling on orders, a U.S. mariner document, the Form I-872 American Indian Card and an Enhanced Tribal Card. U.S. and Canadian citizen children under 16 can come back by land with a birth certificate or other proof of citizenship, and an original, a photocopy or a certified copy all count.

Mexico sets its own rules at the front door. Its immigration agency, INM, asks for a valid passport or passport card, and the card only works for land border crossings and visits within the border zone. Plans that reach deeper into Mexico, or onto a plane, call for the book. The same logic applies at the airport: a passport card can't be used to board an international flight, which matters the moment CBX and a TIJ departure enter the picture. Mexico's embassy also asks every U.S. citizen, minors included, for a valid passport, so the under-16 birth certificate rule covers only the trip home.

Two last checks before you pay for anything else. A REAL ID can't be used to cross into Mexico or Canada, so leave it out of the plan. And if a child under 18 is traveling without both parents, bring a notarized parental consent letter, since one may be needed.

The simplest way to reach the border from central San Diego runs on rails. The UC San Diego Blue Line trolley ends at San Ysidro Transit Center, which shares its address with PedEast at 700 E San Ysidro Blvd. Ride it to the last stop and the crossing is right there, with no parking to find and no car to insure on the Mexican side.

Pay with a PRONTO card or the PRONTO app. An adult fare is $2.50 and stays valid for 2 hours, and PRONTO stops charging once you've spent $6 in a day, so the ride down, the ride back and a hop downtown all fit under that ceiling. You can also tap a contactless bank card or phone wallet, but those taps don't earn the $6 daily cap. For a border day, the card or the app is the better call.

Timing is the other half. The trolley runs roughly 4:30 AM to 1 AM, so a small-hours return needs a backup, and that backup comes with a local backstory. MTS shares part of its rail line with freight companies that run their trains overnight, and federal rules don't allow trolleys and freight to operate at the same time. So since early 2025, a bus has covered the gap. Route 910, the Overnight Express, runs 60-foot buses, with about 60 seats and room for up to 90 riders counting standees, between San Ysidro Transit Center and Santa Fe Depot downtown from roughly 12:30 AM to 5 AM, every 30 minutes, for the same $2.50 fare.

Along the way it stops at Iris Ave, Palomar St., 24th St., 12th & Imperial Transit Center and City College. Those stops sit inside transit centers and don't match every Blue Line station, so pull up the Route 910 schedule and save it on your phone before you head south. A late return goes a lot smoother when the plan is already in your pocket.

Mexico runs its own entry process at the border, through its immigration agency, INM, and the document at the center of it is the FMM, the Forma Migratoria Múltiple. It's Mexico's electronic entry form for foreign visitors who don't hold work authorization. Each one covers a single entry and can run up to 180 calendar days, counted from the moment your migratory stamp goes on.

So do you need one for a quick day in Tijuana? The published guidance disagrees, and it helps to know how. The U.S. State Department tells every land traveler to apply through INM, and that includes trips that stay within the 12-mile border strip. Mexico's embassy, meanwhile, publishes an exception for border-area visits shorter than 72 hours. When two government sources point different ways, the smart move is the one that can't go wrong: complete the FMM online before you leave, print it, and keep it with your passport until you're home.

INM adds a useful note of its own. Paying the fee through its portal doesn't guarantee entry to Mexico, because the officer at the port still has the final say. Bring the right passport document, have the printed form ready, and follow the direction you're given on-site.

That passport choice ties back to the documents step. A passport card covers land crossings and border-zone visits only, so if the day turns into a trip farther south or ends with a flight, the passport book is the one to have in your bag.

Coming back north through San Ysidro, you'll choose between general processing and Ready Lane, and the choice comes down to what's in everyone's wallet. Ready Lane runs on physical cards with an RFID chip, and every traveler 16 and older in your group needs one.

The eligible cards are specific: a U.S. passport card, an Enhanced Driver's License, an Enhanced Tribal Card, an Enhanced Border Crossing Card, an Enhanced Permanent Resident Card, or a Trusted Traveler card from NEXUS, SENTRI, Global Entry or FAST. CBP restated that list in December 2025.

Here's the California wrinkle. Enhanced Driver's Licenses come from only five states, Michigan, Minnesota, New York, Vermont and Washington, plus four Canadian provinces. California doesn't issue one, so for most San Diegans the way into Ready Lane is a passport card or a Trusted Traveler card.

Just as useful is knowing what stays out. A passport book, a REAL ID, a birth certificate, a DMV receipt and a temporary notice don't qualify. The passport book on that list works fine for general processing, and it's still the document this guide recommends for the whole trip. It simply belongs in the other line. If even one person 16 or older in the group lacks a qualifying card, everyone uses general processing together.

Once crossing to Tijuana becomes part of your regular week, SENTRI starts to make sense. It's CBP's Trusted Traveler program for the southern land border, giving pre-approved, low-risk travelers expedited clearance through dedicated primary lanes at the southern land ports. It's a longer-term investment, so it follows the one-trip lane decisions in this guide.

Getting in takes patience. Every applicant goes through a rigorous background check and an in-person interview, and approval is discretionary. The application fee is $120 and non-refundable, and the card is valid for 5 years. Families get a break: a minor pays no fee when a parent or legal guardian is already enrolled or has an application pending. There's no age or citizenship requirement, though applicants under 18 need a parent or guardian's consent.

The car is part of the plan too. To use the dedicated lane while driving, register the vehicle you'll actually cross in. Each additional vehicle costs $42, up to 4 vehicles, and a replacement card runs $25. Apply through the Trusted Traveler Programs system months before you expect to need it.

A SENTRI card also pulls double duty. As a Trusted Traveler card, it counts toward CBP's accepted documents for returning by land and qualifies for Ready Lane, so one card covers a lot of the decisions in this guide.

Nobody can promise how long the line home will be, on a Sunday or any other day. No one publishes a fixed wait for San Ysidro or Otay Mesa. What CBP does publish is more useful: a live Border Wait Times feed that tracks each crossing lane by lane.

The feed breaks the ports out one by one. San Ysidro pedestrian runs 24 hours with up to 22 lanes. PedWest shows its 6 AM to 2 PM window. San Ysidro CBX runs 24 hours, and so does the Otay Mesa passenger vehicle crossing. Each one shows how many lanes are open and the current wait estimate. Pick the exact port and lane you'll use, since a neighboring crossing or a different lane answers a different question.

Check it twice. Once before you head south, to get a feel for the day, and again right before you join the return line. A posted estimate can change while you're on your way to the port, so build a big cushion into the evening on the U.S. side. Flights, show tickets and childcare handoffs belong well clear of the crossing, never directly behind it.

Driving your own car into Tijuana adds one step that comes before everything else: Mexican liability insurance, bought before you leave San Diego. The State Department's Mexico advisory says it's required for every vehicle, and a U.S. auto policy doesn't satisfy the requirement. The same advisory warns that an uninsured driver involved in a collision can be arrested, regardless of who was at fault.

Then look at the car and the people in it. Only U.S. citizens and permanent residents may drive a U.S.-registered vehicle into Mexico, and if someone other than the owner is behind the wheel, the owner has to be present. Check the plate and the current registration sticker before you go. The good news for a Tijuana trip is that Baja California requires no separate vehicle import permit, unlike Mexico's interior.

This step comes last in the guide because it only applies to drivers, and there's a middle path worth considering. MTS runs free park-and-ride lots up the Blue Line at Iris Avenue and Beyer Blvd, with a 24-hour limit. Park there, ride the trolley to San Ysidro Transit Center, and walk across through PedEast with nothing to insure.

If you do drive, pair this step with the live wait check. The Otay Mesa passenger vehicle crossing has its own line in CBP's feed, so look at the exact port you'll use for the drive home.