Yes, Truely offers unlimited data eSIM plans for Montenegro. The provider sells a range of validity options that begin at 1 day and extend through 30 days, with prices that start at $6.32 USD for the 1‑day plan and rise to $104.91 USD for the 30‑day plan. All plans are marketed as unlimited and allow tethering; however, the data may be throttled after heavy usage because of a Fair Usage Policy.
If you are concerned about possible speed restrictions or want to confirm the specifics of the Fair Usage Policy, it is advisable to contact Truely directly. They can provide details on the typical amount of data that is available at normal speed and whether any additional conditions apply to the unlimited plans in Montenegro.