Choosing a base that forgives a missed nap
In Mexico City, families with children under five do best in Condesa or Roma Norte, where leafy streets, flat pavements and small plazas let you walk ten minutes and stop. Both sit on Line 1 of the Metro (Insurgentes, Sevilla) and near the Metrobús on Avenida Insurgentes. Parque México and Parque España anchor each neighbourhood with shade, benches and play areas. Mid-range apartments and small hotels in these colonias commonly run higher than chains near the airport, but you trade a taxi ride for walkable afternoons. Airport transfers by authorised taxi take roughly 30 to 50 minutes depending on traffic.
Coastal breaks split into two useful shapes. Cancún's Hotel Zone has calm, shallow water on the north side and resort pools that absorb a rainy hour, but it is car-dependent and loud. Playa del Carmen's Centro and Playacar offer shorter walks to the beach and to Quinta Avenida, though the avenue is busy after dark. For calmer water and shorter transfers, look at Puerto Morelos: a small grid, a reef close to shore and a 20-minute drive from Cancún airport. Book the Riviera Maya only if you plan to spend most days within a short walk of the room.
A morning block, a long lunch, an afternoon block
Mexican family life runs late, and adjusting to it helps. Plan one outing between 9am and noon, then a sit-down lunch from about 1pm, when restaurants are quiet and high chairs appear without asking. In Mexico City, the Bosque de Chapultepec's first section has flat paths, a lake with rowboats and the free Castillo views; the Museo Nacional de Antropología is large enough to overwhelm small children, so pick two halls and leave. Sunday brings the closed Reforma avenue for cycling, which suits strollers and scooters. On weekday afternoons, the Coyoacán plazas offer room to run and ice cream within a few metres.
In Oaxaca, the zócalo and the adjoining Alameda de León form one continuous, mostly flat walk with benches, balloon sellers and constant shade in the late afternoon. The Jardín Etnobotánico needs a guided entry, so book a morning slot and keep it under an hour. The city sits at about 1,550 metres, and the hill up to the Auditorio Guelaguetza is steep with a stroller; skip it. San Cristóbal de las Casas suits older children better: cobbles and altitude make pushchairs hard work, though the central plazas are compact and calm.
Getting between places without wrecking the routine
Distances that look short on a map are long in a day. Mexico City to Oaxaca is roughly six hours by coach on toll roads, or an hour by air; the coach seats recline and stop midway, but a night departure rarely works with small children. Oaxaca to the coast at Puerto Escondido is a winding six to seven hours by road, or a short flight; the road is not the place for car sickness. Between Cancún and Playa del Carmen, the ADO coach runs frequently and takes about an hour, and from Playa to Tulum add another hour. If you plan two bases, choose ones an hour or two apart.
Best months for this kind of trip are February to April, before the heat and the rains; May and June are hot inland but still workable if you keep mornings and pools. September and October bring the heaviest rain and the quietest hotels on the coast. In Oaxaca, avoid the weeks around Day of the Dead unless you enjoy crowds — it is spectacular and exhausting. Carry cash for markets and small cafés, and check that your accommodation has a fridge, a cot and a lift before booking; top-floor walk-ups with a sleeping toddler are a false economy.
What I would book, and what to skip
For a first trip with children under five, I would book five nights in Condesa in Mexico City and four in Puerto Morelos, flying out from Cancún. Condesa gives you flat morning walks, parks within two blocks and easy airport access; Puerto Morelos gives you shallow water, a short transfer and a town small enough to walk end to end in fifteen minutes. That pairing needs no long overland day and no night coach, which is the single biggest saver of adult patience.
Skip the full-day pyramid excursions. Teotihuacán is a 90-minute drive each way from central Mexico City, with sun and steps at the site; Chichén Itzá adds a two-and-a-half-hour drive from the coast and a long, hot circuit. Instead, take the short boat out to the Puerto Morelos reef, which takes about two hours door to door. Also skip the Monumento a la Revolución lift and the Torre Latinoamericana on clear weekends — queues eat a nap window. Use hotel storage for bags on departure day, and ask for a late checkout when you book.