Harry, 35, flew to London on a commercial flight and was photographed carrying his own bags at a train station in Edinburgh, Scotland, where he is attending a working summit Wednesday for Travalyst, the sustainable travel initiative he launched in September.
Harry, the sixth in line to the throne, asked to be introduced as just Harry at Wednesday's summit, dropping his royal titles, according to ABC News royal contributor Omid Scobie.
"This was an informal event with a lot of people from the tourism and leisure industry meeting for the first time and I think Harry was keen to break the ice and to make it clear he was there in a personal capacity," Scobie told "Good Morning America." "This wasn’t a royal engagement and there was no palace presence."
Harry and Meghan's last day as working members of Britain's royal familyis March 31. The couple's office at Buckingham Palace, their headquarters for the past year, will be closed the next day, April 1.
In their new roles, Harry and Meghan will no longer use their HRH titles and will no longer represent Her Majesty, according to guidelines announced by Buckingham Palace in January.
Duchess Meghan did not join Harry at the event. The couple and their 9-month-old son Archie are currently living on Vancouver Island.
Prince Harry's Travalyst initiative is an effort he plans to continue to work on in his new role as a non-working member of the royal family.
"Travalyst is very much part of Harry’s next chapter and an extremely important initiative that will have major positive impact on the tourism industry and communities around the world," said Scobie. "What’s great about this is that it’s Harry not telling people not to travel, he just wants to create industry-wide transparency that allows the consumer to be informed enough to make their own eco-conscious decisions as they explore the world."
The name Travalyst, comes from the words travel and catalyst, according to a post shared on Harry and Meghan's Instagram account.
The initiative is led by partnerships with Booking.com, Ctrip, Skyscanner, TripAdvisor and Visa, and aims to "spark a movement to transform the future of travel, putting communities at the heart of the solution," according to the post.
"I want to help create a platform where all of us concerned about these issues can work together, where competitors can unite and incentivize a positive systemic change," Harry said Tuesday. "There's a reason why this hasn't been tried before, but with our partners we have the best shot."
Harry and Meghan were photographed using a private jet last summer and quickly faced backlash given their previous statements on environmental protection and climate change awareness.
Elton John then spoke up to defend Harry and Meghan, saying the couple stayed at his home in Nice, France, and he provided them with a private jet in order to "maintain a high level of much-needed protection."
"To support Prince Harry's commitment to the environment, we ensured their flight was carbon neutral, by making the appropriate contribution to Carbon Footprint." the musician wrote on Twitter.
Harry responded to the criticism himself when he announced the launch of Travalyst at an event in Amsterdam in September.
"I spend 99% of my life traveling the world by commercial [aircraft]," he said. "Occasionally, there needs to be an opportunity based on a unique circumstance to ensure that my family are safe, and it's genuinely as simple as that."
"But for me, what it is is about balance," he added. "If I have to do that -- not a decision that I would want to take -- but if I have to do that, then I will ensure, as I have done previously and I will continue to make sure that I do, to balance out that impact that I have."
"And I have always offset my CO2," Harry said, referring to his carbon footprint.