This is the PR version of Craigslist. Almost everyone in PR uses ClasificadosOnline instead of Craigslist.
Select property type as FINCA. You can also list a price range and area of the island to narrow the search. Unfortunately, they do not have a way to search by the number of acres or cuerdas. This is a fatal flaw that makes the site far less useful. Be sure to contact ClasificadosOnline to tell them they should implement a sort feature by number of acres. It’s sad that they are not as smart in site design as they are in building market share. This is a no-brainer, yet they still haven’t done it. Puerto Rico does it better? Landwatch below allows you to sort by number of acres, but Landwatch has almost 0% market share for farm/land listings in PR.
This site has the second largest market share for online classifieds in PR. They too fail to allow a sort option for the number of acres or cuerdas.
Landwatch is not as useful as it could be, because too many idiots list the square meters of their property in the acreage field. So when you search for large acreage, instead you find single lots.
This one has almost no listings.