Barron Trump took a stroll around the White House with his parents on Friday ... the first time he's been seen there since Donald Trump took office.
The president's 10-year-old son walked across one of the lawns with Melania -- who was decked out in red -- before boarding Marine One to start a weekend trip to Mar-a-Lago.
We broke the story ... Barron and his mom will be moving to 1600 Pennsylvania Ave. to stay in June. Guessing he scoped out a bedroom during his visit.