The Mass in Latin? Or the Tridentine Mass.
Many, too numerous to list, celebrate the Ordinary Form in Latin either occasionally or regularly. Solesmes, St. Wandrille in France are two that I know of for certain, that use Lati exclusively for their liturgy. There are also women’s monasteries that celebrate the OF in Latin. One just outside of Montreal. But if you’re looking for a male vocation, that won’t be useful!
For the EF, there are many in Europe. In the US, Clear Creek for sure. In Europe, the monks of Norcia in Italy; Randol, Fontgombault and Barroux in France for sure.
Are you considering a vocation? If so bless you, but a caveat, the priority is to live according to the Rule of St. Benedict, under the rule of an abbot. If your first priority is the form of the Mass rather than the Benedictine charism, you will be found out during postulancy and noviciate and may not be accepted. Monastic life is not as easy as it seems to outsiders and the monastic part of the vocation is far more important than what form of liturgy is used. Liturgy will of course be extremely important in its observance but not necessarily form.
Moreover in a monastery, there’s much more than just the Mass to the liturgy. If you go to a monastery using the EF Mass (and many using the OF like Solesmes), the full Benedictine cursus of psalms will be used, 250 per week. Vigils (matins) will last well over an hour, even up to 3 hours on major solemnities, and there’s lots of repetition of the same psalms (Terce, Sext, None and Compline; Psalms 66, 50, 148-150 every day at Lauds), Prime will be said so your mornings will be almost continual liturgy from around 4-5 am for 2-3 hours depending on days. At the beginning it will seem like Chinese water torture. And all in Latin.
The abbey I’m associated with uses a hybrid Latin/French OF Mass, with the Propers and Ordinary in Latin/Greek from the Graduale Romanum. Their psalm cursus is the entire psalter in a week (150 psalms), much more reasonable, Monastic schema B.