Yesim sells unlimited‑data eSIM plans that are valid in Costa Rica. The provider offers several validity options: 1 day, 7 days, 15 days, and 30 days, with prices ranging from about $10.63 USD for a single‑day plan to $68.53 USD for a 30‑day plan. Each plan allows tethering and is marked as unlimited, but the description notes that speed may be throttled after heavy use according to a Fair Usage Policy.
If you are concerned about potential speed restrictions, it is best to contact Yesim directly to confirm whether a Fair Usage Policy applies to the specific Costa Rica plan you choose and to find out the typical amount of data that can be used at normal speed before throttling occurs.