Mask mandates exist to varying degrees throughout Europe, and the details — inside, outside, fabric, N95 and more — are dizzying.

My wife and I are both fully vaccinated and we’re planning to visit Germany, Austria, the Czech Republic and France next month. I can’t seem to find consistent information online as to whether any or all of those countries have mask requirements. There are so many questions: Will fabric masks suffice? Does one have to wear a mask outside? What about respirators like FFP2 or N95 masks? We are happy to comply with the mandates; we just don’t know the specifics. Victor

First things first: Although travel restrictions are starting to crop again throughout Europe, Germany, Austria, the Czech Republic and France are all open to vaccinated Americans without quarantine.

Now on to your question: Mask mandates exist to varying degrees throughout Europe, and you’re right, the details are dizzying. Websites for individual U.S. embassies are helpful, as is the Reopen E.U. website, which has country-specific information about social distancing, masks and more.

But many travelers may find themselves confused about masks even before they leave the United States. Here’s a detailed breakdown of what’s officially required, and where, at critical junctures along the journey.

Are masks required at the airport here at home? If so, which types?

With certain exceptions for passengers with disabilities, masks have been required at U.S. airports since February. That’s regardless of vaccination status, and it will be the case until at least mid-January, according to an emergency amendment issued last month by the Transportation Security Administration.

Guidelines set by the Centers for Disease Control and Prevention hold that a variety of masks qualify under the federal law — store-bought and homemade, medical-grade and fabric — as long as they are snug to the face and made from an unpunctured piece of material. Worn alone, face shields do not qualify as masks, nor do bandannas, neck gaiters or scarves.

What about onboard the flight?

Masks must be worn on flights to, from or within the United States, on both domestic and international airlines. Masks can be temporarily and briefly lifted to eat or drink, but they must be kept on while sleeping. U.S. airlines are generally following C.D.C. guidelines and allowing all types of masks, including fabric masks, to be worn onboard.

Things get more complex on international airlines: Although masks are also required on European airlines, fabric masks won’t suffice on all of them. Lufthansa mandates either surgical or valve-free masks onboard flights to or from Germany, where those types of masks have been required on public transit, in public buildings and in shops for months. Austrian Airlines and Czech Airlines have also mandated medical masks since the winter. Similar requirements are now in place on Finnair, Air France, Swiss International Air Lines and others. Check specifics on your airline’s website.

As for how to stock up: Surgical masks are readily available at online retailers like Amazon or Target. And although it was difficult, if not impossible, to find respirator masks like N95s at the beginning of the pandemic, they are more readily available now. On its website, Wirecutter has a comprehensive breakdown of the different types of medical masks, and where to buy ones you can trust.

And what happens once I land?

Most airport and airline requirements tee up nicely, so travelers can safely assume that the mask they wear in-flight will be the one that stays on through baggage claim.

Are masks required on trains or buses around Europe?

Broadly, yes. Country-specific mask requirements for airplanes and airports generally apply to all forms of public transportation, including trains and buses. But that doesn’t mean standards will be universally enforced; unlike an Air France agent at Charles de Gaulle Airport, for instance, a bus driver in a small French town may not look twice at a fabric mask.

I’d like to eat inside a restaurant or visit a museum. Will I need to wear a mask?

Although indoor masking rules are among the most perplexing parts of a multi-leg Europe trip — just as in the United States, they’re usually set by regional or local governments — signs will be everywhere, from restaurants to museums. When in doubt, just ask.

Travelers may also find an increasing number of commonalities: Many countries, including the ones you’re visiting, are requiring that patrons show some form of proof, be it paper or digital, of vaccination status, recovery from Covid-19 or virus test results in order to enter indoor venues like restaurants. Large, high-capacity indoor sites like museums are requiring masks nearly across the board, regardless of health pass or vaccination status, although exactly which type of mask is acceptable will vary by venue.

The rules at smaller indoor venues like restaurants are at the whim of a number of factors — from national or city-specific guidelines to an individual owner’s health policies.

In Berlin, for example, all diners must a wear a surgical (or stronger) mask until they’re seated. In Paris, individual establishments where health passes are required for entry (say, at a restaurant) can decide whether or not to mandate masks, but one cafe’s policy may be different from its neighbor’s. In the Czech Republic, respirator masks are technically supposed to be worn unless patrons are eating and drinking, but it’s hard to imagine every restaurant enforcing those standards.

Travelers may also find head-spinning inconsistencies: Austria is waiving face mask requirements indoors and out for anyone who’s vaccinated; in Vienna, though, masks must be worn in shops, movie theaters and cultural venues like the Vienna State Opera. Although surgical masks have been Germany’s baseline since the winter, one Times reader emailed to report that, on a recent trip, certain hotels and shops were insisting that patrons wear N95 respirator masks, and even going so far as to hand them out.

There are bound to be differences within a country, city or even a block. And public-health rules are almost certain to change, anyway. The surest course is to pack several surgical and respirator masks, read signage carefully and be prepared to make the switch if asked.

Are masks required outside in public places like parks and plazas?

In broad terms: not where it’s possible to social distance, and infractions usually mean fines. But, again, regulations may vary from one locality to the next. Masks are not generally required outside in France, although a handful of departments have reinstituted outdoor mask mandates. If you walk into a park and see that everyone’s masking up — well, it should be pretty obvious what to do.

Sarah Firshein is a New York-based writer. If you need advice about a best-laid travel plan that went awry, send an email to travel@nytimes.com.

Follow New York Times Travel on Instagram, Twitter and Facebook. And sign up for our weekly Travel Dispatch newsletter to receive expert tips on traveling smarter and inspiration for your next vacation.