Two forts, one ticket, and they are a national park. Castillo San Felipe del Morro on the point and Castillo San Cristobal above the Atlantic. One admission covers both for twenty four hours, children under sixteen are free, and the whole thing costs less than a coffee each. Six levels, tunnels, sentry boxes, cannon. Do San Cristobal first because it is quieter.

Ask for the Junior Ranger booklet. Free at either fort desk. Activities scaled by age, and a ranger swears them in and pins a badge on at the end. It is the single best value thing we did with our three anywhere in the Caribbean and it is genuinely free.

Walk the Paseo del Morro at the bottom of the wall. A flat waterside path that runs along the base of the city wall between the two forts. Cats, fishermen, no traffic and no hills, which matters if you have short legs with you. It is the nicest hour in the old city.

The old city empties in the evening and improves. Day trippers and ship passengers leave around five. Plaza Colon and Calle Fortaleza after that are a different place, with music and families out and no queues. If you are staying rather than cruising, this is when to be there.

You need a timed reservation for the main road. Route 191 requires a booked entry slot from recreation.gov and they go days ahead in high season. It costs a couple of dollars. Families turn up without one and get turned away, and it is the most avoidable mistake on this island.

La Mina Falls, Juan Diego and the tower. Yokahu Observation Tower is a walk up from the car park and gives you the whole forest. Juan Diego Falls is a five minute scramble and swimmable. La Mina Falls is the famous one and closed for years after the 2017 hurricanes, so check it is open before you promise it to anybody.

Go in the morning and take a rain jacket. It rains most afternoons and the trails get slippery. Proper shoes, not flip flops. There is no food inside worth eating, so bring lunch.

Mosquito Bay on Vieques is the one. It is the brightest recorded bioluminescent bay on earth and it is not close. If the glow is the reason you are going, go to Vieques and stay the night. The others are good. This one is the thing people describe for years afterwards.

Book the darkest nights, and only those. The glow is drowned out by moonlight. Aim for the five nights either side of a new moon and treat a full moon booking as money thrown away. Any operator who tells you the moon does not matter is selling you something.

Laguna Grande at Fajardo is the practical compromise. An hour from San Juan, a mangrove channel you kayak through in the dark to reach the lagoon, no overnight required. It is dimmer than Mosquito Bay but it is doable as an evening from the city, and the channel itself is memorable.

La Parguera is the one to skip with children. It is the only one where motorboats are still allowed, which means it is the least protected and the least impressive of the three. It also runs later. If somebody offers you it as the convenient option, that is why it is convenient.

No sunscreen, no repellent, no flash. Anything on your skin kills the organisms. Reputable operators will tell you to shower first and will not let you swim. If yours does not mention it, book somebody else.

The ferry is cheap and it is a lottery. Two dollars a head, about forty five minutes, and residents get priority. Book online the moment the window opens and turn up very early. If the trip depends on being somewhere at a particular time, fly instead. I have had families lose a whole day to a full ferry.

Flamenco Beach on Culebra earns the ranking. It is on every best beaches list and it deserves to be. White sand, calm shallow water for small children, and two rusting tanks left on the sand from the years the US Navy used the island for target practice, which children find far more interesting than the sea.

Vieques has wild horses and Mosquito Bay. They wander the roads and they are genuinely wild, so give them room. Vieques is the bigger, emptier, rougher of the two and it is where you go for the bio bay. Roads are poor and a 4×4 earns its money.

Hire a car unless you are only doing the old city. Public transport outside San Juan barely exists and taxis get expensive fast. Your US license and your own car insurance usually work, which is worth checking before you pay for the counter policy. Roads are American style, signs are in Spanish and distances are in kilometers while petrol is in litres.

Two airports, and use the second one. San Juan is the main gateway. Aguadilla on the north west coast takes low cost flights and puts you next to Rincon and the surf coast without a three hour drive.

Old San Juan is walkable and steep. Cobbles, hills and narrow pavements. A pushchair is hard work. Free trolleys loop the old city and are the answer with small children or tired ones.

Dollars, and cards work everywhere. No exchange rate, no foreign transaction fee, no conversion trick at the card machine. Carry some cash for chinchorros, beach parking and the ferry, which are cash businesses.

Your health insurance works and so do your prescriptions. It is a US territory, so the pharmacy chains are the ones you already use and your plan generally applies. This is a genuine reason families with a medical situation choose Puerto Rico over anywhere else in the Caribbean.

Spanish is the working language and English is widespread. San Juan, the resorts and the tourist areas run in English. Small towns and the mountains do not, and a little Spanish is appreciated the same way it is anywhere. Nobody will be stuck.

Power cuts still happen. The grid has never fully recovered from 2017 and outages are a normal part of life. Good hotels have generators. Ask. A power bank and a torch in the bag is sensible rather than paranoid.

Against Aruba or Turks and Caicos. Those two have better beaches and better resorts and they cost considerably more. They also need passports for everyone. If your family has valid passports and wants a reliable beach week, they win. If you want a country to explore rather than a resort to sit in, Puerto Rico wins easily.

Against the US Virgin Islands. The other no passport option, and St John is two thirds national park and beautiful. But the USVI is small, expensive and short on things to do beyond the water. Puerto Rico has a rainforest, a colonial capital, a mountain range and two side islands. More depth, less polish.

Against Mexico. Mexico is cheaper and has more all inclusive choice. Puerto Rico needs no passport and no currency and your phone works. For a first trip that is meant to feel foreign without any of the friction, Puerto Rico is the softer landing.

If you are cruising. San Juan is both a port of call and a home port, and it is one of the few Caribbean stops where a port day is genuinely worth staying in the town for. Ours was. Add nights either side if the fare allows it.

Do the Junior Ranger program. Free at the forts and at El Yunque, scaled by age, and it ends with a ranger and a badge. It is the highest return on effort of anything on this island and it is the one piece of this page that comes from watching my own three do it.

Know which beaches are calm. The north coast faces the Atlantic and has surf and rip currents. Condado and Ocean Park in the city are lively rather than gentle. For small children, the south and west coasts, Flamenco on Culebra and the calm ends of the Fajardo beaches.

The coqui frogs are a bedtime feature. They start at dusk, they are loud, and they are on the national crest. Children either love them or need a fan on for the white noise. Both outcomes are common.

Heat and sun are the real hazards. Eighty degrees plus humidity all year. Mornings out, afternoons in water or in shade, reef safe sunscreen because the mangroves and the bio bays depend on it, and more water than you think.

How much a national park changed the day. I expected a pretty old town and a walk. What we got was a fort the children were allowed to run on and a booklet that held them for hours. It cost almost nothing.

How foreign it feels for somewhere so easy. Domestic flight, dollars, your own phone, and then blue cobblestones, Spanish on every sign and four hundred year old walls. The gap between how little effort it takes and how far away it feels is the whole appeal.

That 2017 is still present. Not as a warning, as a fact. You see it in the roofs, in the closed trails and in how people talk about the power. Anyone going should know that and behave like a guest who knows it.