Jill, 24, took to Instagram to share a picture of the duo and their nearly 4-month old son.
"¡Hola amigos! Thank you for your prayers and support! It's been one month since we departed the U.S. for Central America," she captioned the photo of the family, including a link to their newest blog post.
Derick, 26, also shared his own photo of the couple standing in what appears to be a busy marketplace carrying food and provisions, with baby Israel David strapped onto Jill.
"One month ago today we arrived in Central America! It's been quite an adventure adjusting to life here," he wrote. "Thank you for your prayers and support!"
In the blog post written by Jill, she details the family's "busy and adventurous last month in several different Central American countries."
"We visited many villages and town squares where we performed dramas and programs, evangelized, helped lead a couple youth conferences, organized a regional soccer tournament, met with government officials to discuss pressing issues, worked on construction projects, and made home visits," she wrote.
Jill is also attempting to learn Spanish – but thinks Israel will pick it up even faster.
"He is already becoming a local as he loves to nap anywhere there is a 'hamaca' (hammock)," she added.
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According to the post, the couple will be in language school for this month and then plan to return to the United States for a short time before heading back.
The end of the first month of their mission trip comes almost three weeks after TLC officially cancelled the family's reality show, 19 Kids and Counting, following Jill's brother Josh Duggar's molestation scandal, which broke in May.