It's been more than nine months since the coronavirus pandemic was declared on March 11, and it's been a rocky road for the travel industry ever since. While there's plenty of reason for optimism as countries reopen their borders, airlines ramp up flight schedules and cruise lines gear up to resume operations amid increased testing and elevated health and safety protocols across the sector, travel continues to be heavily impacted by the coronavirus crisis. With 2021 just around the corner, let's look back at how we got here.

Two months before the coronavirus pandemic was declared, the Centers for Disease Control and Prevention (CDC) began screening for the virus at three U.S. airports, including John F. Kennedy International, San Francisco International and Los Angeles International. Days later, on January 21, a Washington state resident became the first person in the U.S. with a confirmed case of COVID-19. Nonetheless, there were no widespread restrictions on travel at this time.

President Donald Trump tightened travel restrictions on China in February. Beginning February 2, travelers en route to the United States were required to have left China or potentially face two weeks in quarantine (if they had been in Hubei province) or health screenings upon arrival (mainland visitors). Countries such as Australia, Germany, Italy and New Zealand imposed similar travel restrictions at this time as the virus continued to spread.

March was by far the busiest month for COVID-19-related travel restrictions. After the World Health Organization (WHO) declared COVID-19 a pandemic on March 11, the Trump administration issued a travel ban on non-Americans who visited more than two dozen European countries within 14 days of coming to the United States. On March 17, the United States and Canada mutually agreed to close their border to non-essential travel and, three days later, the United States and Mexico mutually agreed to close their border to non-essential travel.

On March 25, Alaska began requiring visitors to fill out a travel declaration and complete a two-week quarantine. Meanwhile, Hawaii Gov. David Ige issued an automatic two-week quarantine for people traveling to the state on March 17 and requested that would-be visitors postpone their trips for 30 days.

The chaos of mid-March also impacted cruise lines, which agreed to suspend sailings for 30 days to slow the spread of COVID-19. The suspension of major cruise operations in the U.S. would eventually be extended through the end of 2020.

After mutually agreeing with Canada and Mexico to close borders to non-essential travel due to the pandemic in March, the U.S. announced that travel restrictions with its North American neighbors would be extended another 30 days on April 20. The extensions would continue throughout the year and, as of December, U.S. land borders with Canada and Mexico will be closed to non-essential travel through at least January 21, 2021.

Many of the country's most sought-after national parks began phased reopenings ahead of Memorial Day Weekend, limiting the number of visitors and enforcing strict face mask and social distancing requirements. However, Hawaii and Alaska both extended their 14-day quarantine requirement for out-of-state travelers into the summer. The latter would allow visitors to bypass self-isolation with a negative test result taken within 72 hours of arrival.

The summer began with Saint Lucia beginning a phased reopening on June 4. The Caribbean island was among the first to welcome back Americans but would be joined by many others in the weeks and months to come. In late June, the governors of Connecticut, New Jersey and New York announced a joint travel advisory requiring visitors traveling from states with high COVID-19 infection rates to quarantine for at least 14 days. This list, based on a seven-day rolling average of the number of infections per 100,000 residents, has been updated on multiple occasions over the second half of 2020.

The European Union reopened to non-essential travel on July 1, permitting entry to visitors from 14 countries. However, the U.S. was left off of the list due to its rising case numbers. A handful of other popular destinations resumed tourism in July, including Bermuda, Egypt, French Polynesia, the Maldives and Turks and Caicos, among others. Walt Disney World Resort theme parks also began welcoming back guests in mid-July with enhanced health and safety measures and a new reservation system in place to control capacity.

August saw even more coveted Caribbean hotspots such as Dominica and Anguilla reopen their borders while Greece began welcoming back cruise traffic at six ports, including Piraeus, Rhodes, Heraklion, Volos, Corfu and Katakolo. In the U.S. Florida Gov. Ron DeSantis rescinded an executive order requiring travelers from Connecticut, New Jersey and New York to self-quarantine for 14 days upon arrival on August 6.

More destinations, including the U.S. Virgin Islands and Bali, lifted travel restrictions in September while the Dominican Republic eliminated its previous requirement that travelers present a negative COVID-19 test result upon arrival, making the Caribbean country more accessible heading into the fall. Domestically, New Mexico Gov. Michelle Lujan Grisham announced that out-of-state travelers from states with a five percent positivity rate or greater or a new case rate greater than 80 per 1 million residents would be required to self-quarantine for 14 days upon arrival unless possessing proof of a negative COVID-19 test taken within 72 hours of entry.

After multiple delays, Hawaii finally rolled out its pre-travel testing program in mid-October, allowing out-of-state visitors to bypass the state's mandatory 14-day quarantine with a negative COVID-19 test result. At the end of the month, New York Gov. Andrew Cuomo announced visitors and returning residents would be required to take a COVID-19 test within three days of arriving in New York and quarantine for three days before taking another test on the fourth day.

In mid-November, Pennsylvania's Secretary of Health issued an order requiring out-of-state travelers and returning residents to quarantine for at least 14 days upon arrival or provide proof of a negative COVID-19 test taken within 72 hours of entering the state. Meanwhile, Hawaii Gov. David Ige announced that travelers need to have their negative COVID-19 test results in hand prior to departure or otherwise face a two-week quarantine beginning November 24.

As of late-December, several U.S. states continue to restrict travel, requiring some holiday travelers to quarantine or provide proof of a negative COVID-19 test result before being permitted to move about freely. Meanwhile, dozens of countries around the world have begun imposing bans or restrictions on travel from the U.K. amid the outbreak of a coronavirus variant that health authorities say can spread faster than others.