Vaccine passports won't be federally mandated in the US, but you might need one for international travel. Here's what it could look like.

• Vaccine passports show that you have received the coronavirus vaccine or recently tested negative.
• Coronavirus vaccine passports may be required to travel internationally, as Insider reported.
• Organizations are working on passports, but Dr. Anthony Fauci said they won't be federally mandated.

As the coronavirus vaccine becomes more readily available, leaders in travel, tech, and politics are increasingly talking about vaccine passports: documentation that proves someone has received the coronavirus vaccination or a recent negative COVID-19 test result.

While most travelers aren't required to be fully vaccinated - except for people who want to take a cruise - this may change once more people become vaccinated, according to Forbes. And at the very least, a vaccination passport would allow many travelers to skip quarantines or pre-arrival diagnostic testing.

The Centers for Disease Control and Prevention also updated its guidelines on Friday, saying that fully vaccinated people can travel safely in the US without a COVID-19 test or self-quarantine.

However, vaccine passports won't be federally mandated, as Dr. Anthony Fauci, President Biden's chief medical adviser, told the Politico Dispatch podcast on Monday, as Axios reported.

Still, it's likely vaccine passports will become essential for international travelers in the coming months, as the Associated Press and Insider previously reported.

What vaccine passports look like

Digital passports could look similar to airline boarding passes with a scannable code that you could pull up on your smartphone or print out ahead of time, The Washington Post reports. For some travel, you may even be able to use the vaccination record card you receive during vaccination.

In Hawaii, for example, state officials are considering issuing vaccination passports for people to travel in and out of Hawaii and across islands, local station KHON2 reports.

But while an app is being developed, Hawaii Lt. Gov. Josh Green has said officials at the airport could simply check vaccination cards to make sure they're legitimate.

While it may not be required for domestic travel, the Biden administration is reportedly working on a vaccine-passport program for people to prove they are vaccinated before entering crowded areas like cruise ships, venues, and restaurants, according to The Washington Post.

In Europe, the EU is working on a similar, joint vaccination passport that supporters hope will be up and running by June, just in time for peak summer tourism, The Washington Post reported.

Israel already has a digital passport app in use called a "green passport," which is issued by the Israeli government to people who are fully vaccinated.

Certain countries already require proof of vaccination against other diseases upon entering the country, and some travelers use a paper International Certificate of Vaccination for proof.

To accommodate an increasing desire to open up travel, digital health passport apps that store and display proof of vaccination are already emerging on the market, like CommonPass, the International Air Transport Association (IATA) Travel Pass, and Health Pass by CLEAR.

The World Health Organization is also working on a Smart Vaccination Certificate, which will provide guidelines and standards for digital vaccine passports.

Governments and airlines have yet to standardize vaccination requirements and how people will need to prove they're safe to travel, and some travel industry leaders have raised concerns about mandatory vaccinations being discriminatory.

But others remain hopeful.

"Vaccine passports, if done right and done equitably, can be a way to help us get back to normal more quickly," Lawrence Gostin, director of the O'Neill Institute for National and Global Health Law at Georgetown University Law Center, previously told Insider. "It can make all the things we love to do safer: travel, going to a sporting event, getting back to work."