The long wait is over.

After years of planning and myriad delays, the European Union's Entry/Exit system (EES) will go live on Oct. 12.

While nothing has changed when it comes to the rules of who can enter the EU, and how long they can stay, the new system will track cross-border movements in the Schengen area of 29 countries. This will be done by capturing the biometric data of visitors -- just as other countries, including the U.S., already do.

How will it work, and how could it impact your vacation? Here's all you need to know.

What is EES?

The EU's Entry/Exit System will capture biometric data from non-EU citizens entering the Schengen area (essentially all EU states except Cyprus and Ireland, plus Switzerland, Iceland and Norway). In the same way that visitors are fingerprinted entering the US, travelers to the EU will be fingerprinted when they enter the bloc -- and again, when they leave.

The aims are two-fold: to reduce crime and illegal cross-border movement, but also to ensure that visitors are not overstaying their welcome.

Third-party nationals, as non-EU citizens are termed, are only allowed to spend 90 out of every 180 days in the bloc.

How will it work?

The system should be simple, checking faces and fingerprints against the biometric data already on record. But creating the record will be a little more time-consuming. The first time a traveler encounters the system, they will have their photo and fingerprints taken, and passport data recorded. Border points across Schengen have already installed lines of self-service kiosks for travelers to register.

Once registered, on subsequent visits, your photo and fingerprints will be checked against what is already on the system. If you have a biometric passport and there are E-gates at your border crossing, you should be able to enter with that.

Will it be everywhere?

Not at first. To avoid the logistical logjams that had been predicted, the rollout is being staggered. Each member state can decide where and how they want to implement the system. The only requirements are that at 30 days in, countries must be registering 10% of travelers. By 90 days, they should be registering 35% of travelers, rising to 50% at 150 days. By day 180, on April 9, countries must be registering all travelers in the system.

At least one border crossing point in each EU country will need to have the system operational from October 12. The European Commission advises that member states roll it out at various crossing points by sea, air, and land.

Outside that guidance, countries are free to implement it as they want.

What biometric data will be collected?

Your fingerprints and a photo of your face will be captured.

Also recorded will be your passport information (full name and date of birth), the dates and places of entry and exit into Schengen. If you were refused entry, that will also be noted.

You'll also be asked where you're staying and whether you have funds to cover your trip.

Will there be delays?

Officials are trying to minimize delays by rolling out implementation gradually, according to an EU official. However, they warn, "there might be some delays at the beginning."

Self-service kiosks at entry points to register your initial details should help make things faster.

Is this the end of passport stamps?

Not quite yet. Because the system is rolling out over the next six months, your passport will still be stamped at border crossings -- even if you've gone through EES. That's so that crossings not yet using the technology can still keep track of your days in the EU. Once the system is fully effective, which should be on April 9, the passport stamps will end.

What happens if I'm refused entry?

It'll be recorded on the system and visible at any future entry points.

Will I have to redo this every time I go to Europe?

The information will be stored for three years, so if you travel regularly into Schengen it will keep renewing. However, if you don't travel in the next three years, you'll need to reregister the next time you travel to the EU. There are strict rules on how your data is handled -- see the website for full details.

I am an EU citizen. Do I have to register?

No, because the EU already has your biometric data. The same goes for EU residents, regardless of their nationality. Legal residents will already have had their biometric data captured as part of the residency process.

The full list of those exempt from EES is here.

Are children exempt?

Children under 12 do not have to provide fingerprints, but do have to go through the rest of the process.

Do British citizens need to register?

Yes. Since Brexit, British citizens are counted as third-party nationals along with the rest of the world. The only exception is for Brits who are legally resident in the EU, or covered by the Withdrawal Agreement.

How do I calculate my 90 days in a 180-day period?

If you're not great at math, there's a handy official calculator here.

Sanctions for overstayers range from fines to deportation and bloc-wide bans.

When will ETIAS start?

ETIAS is the new pre-travel visa waiver that will be launched by the EU, similar to the ESTA for travelers to the U.S. Having been postponed multiple times, the launch is now down for the end of next year, "probably," according to an EU spokesman. An information campaign will be launched six months prior, so there'll be notice.

Traveling to the European Union is about to get more complicated. Here's what you need to know