Free castles and museums in Yvelines this Sunday, October 4, 2026 — the first Sunday of the month.

As regulars of the first Sunday of the month, we’re heading out to enjoy the free museums and monuments of Yvelines this Sunday, October 4, 2026. In the 78, several cultural sites open their doors for free, but not all on the same schedule. A quick heads-up before you go: the major national monuments like the Château de Versailles or Rambouillet’s don’t return to free admission on the first Sunday until November. In September, it’s mainly departmental and municipal museums that are stretching out the welcome.

While Paris showcases new openings like the Orsay Museum, the Quai Branly Museum, or the Arc de Triomphe, the Yvelines aren’t far behind. Here are the places to explore for free this Sunday.

• The National Archaeology Museum – Saint-Germain-en-Laye Castle

We head to Saint-Germain-en-Laye, inside its historic château, to discover the National Archaeology Museum. The museum houses some of the world’s richest archaeological collections, tracing the story of humanity and its “inventions” from the origin of man up to the Merovingian era. A series of temporary exhibitions allows visitors to learn more about our ancestors in a playful and educational way.

• The Port-Royal-des-Champs National Estate

The domain, the ruins of the Port-Royal-des-Champs Abbey, and the national estate of the Granges of Port-Royal together form the Port-Royal-des-Champs National Domain. Set off to discover the abbey ruins razed by order of Louis XIV and the museum housed in the former "Petites Écoles" building. On the first Sunday of every month, park admission is free.

• Poissy Toy Museum

The Toy Museum, opened in September 1976, sits at the heart of the gatehouse of the Royal Saint-Louis Priory. This museum houses a vast collection of nearly 14,000 objects, including 600 games and toys that whisk visitors on a fascinating journey through the world of play, from Antiquity to the present day. Dolls, plush toys, miniature vehicles and racing tracks, board games and construction sets, science kits, jump ropes, or figurines… Styles come and go, technologies evolve, but children's passions remain timeless. To discover games of yesterday and today, take advantage of free admission on the first Sunday of every month.

• To be read
• This week's top picks in Paris and Île-de-France for September 28 to October 4, 2026.
• Free museums in Paris and free monuments in Île-de-France: the top cultural deals
• 10 top outings in Yvelines for this weekend of September 26–27, 2026

• Hôtel-Dieu Museum

The Hôtel-Dieu Museum houses a collection spanning centuries of artistic creation across three levels. Located in Mantes-la-Jolie, just steps from the Notre-Dame Collegiate, the Hôtel-Dieu Museum offers a look at the city’s medieval past as well as the works of artist Maximilien Luce. Admission is free on the first Sunday of every month.

• The Iron House

On the first Sunday of every month, from October to December, the Maison de Fer offers a free, 30-minute guided tour with no reservation required. The Maison de Fer in Poissy, a landmark dating from 1896, is an unconventional museum dedicated to the city of Poissy, nestled in the heart of Meissonnier Park. Explore its distinctive industrial architecture, its history, and the broader story of Poissy’s evolution.

• The Chevreloup Arboretum

You may not know it, but the Arboretum de Chevreloup is also free to visit on the first Sunday of the month. A vast natural and landscaped expanse spanning 200 hectares, home to an exceptional collection of 2,500 plant species, the Arboretum of Versailles-Chèvreloup is an integral part of the royal domain of Versailles. For nearly a hundred years, the Muséum national d’Histoire naturelle has been developing a true living museum of trees here. The park welcomes visitors from 10:00 a.m. to 5:00 p.m., with the last entry around 4:00 p.m.

• The Carriage Gallery

The Carriage Gallery, tucked inside the Grand Stables at the Palace of Versailles, is free to visit on weekends, including Sundays that aren’t the first of the month. When you’re in Versailles, it’s a stop that would be a pity to miss, so we take the opportunity to discover these treasures.

So, how about a nice free visit this Sunday, October 4, 2026?

And to go further:

Free museums and monuments on Sundays: the best plans for October 4 in Paris and Île-de-France.
Which free museum to visit in Paris or Île-de-France on this first Sunday of the month, this Sunday October 4, 2026? We’re happy to revive our little monthly ritual: discovering a museum or monument, with no cost involved! Don’t miss the great plans for this Sunday... [Read more]

6 castles with free admission this Sunday, October 4, 2026, around Paris
Châteaux in Île-de-France open their doors for free on the first Sunday of every month, and this October is no exception. A wonderful opportunity to discover our Île-de-France heritage without spending a cent this Sunday, October 4, 2026. [Read more]

Free museums in Paris and free monuments in Île-de-France: the top cultural deals
Are you looking for a free museum in Paris or a free monument in Île-de-France? Free-access venues, free tours on the first Sunday of each month, museums free for under-26s and for teachers: discover the cultural deals you won’t want to miss. [Read more]

10 top outings in Yvelines for this weekend of September 26–27, 2026
The Yvelines (78) kick off the first weekend of autumn with the Chatou Fair, the final days of the Saint-Germain en Live festival, and around twenty flea markets, on September 26 and 27, 2026, just a stone's throw from Paris. [Read more]

What to do in Yvelines (78)? Heritage, good addresses and activities, ideas for outings
Want to get to know Paris Region better? This time, we're taking you to the Yvelines to discover its heritage, places to visit, must-do activities and the best deals of the moment. From castles to walks and good addresses, here's what's in store for you in the 78 département. [Read more]

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