I’m only in RCIA (a recent convert to Catholicism).
A mortal sin is composed of:
- Grave matter
- Full knowledge
- Full consent of the will
You are travelling and it is not your intent to miss Mass.
So it is not a mortal sin. But before skipping mass you should examine your plans. Can you go to Mass on Saturday night (vigil Mass)?
In part, I envy you. If you are going to Prague in the Check Republic, certainly you must see about going to at least one of the beautiful Roman Catholic Churches there sometime. Maybe a morning Mass during the week.
Please do me a favor: if you are able to go to Mass in Prague sometime on your trip, please send me a private message to tell me about it.
Even if it is a city named Prague somewhere else in the world (there are other cities), I cannot imagine it being named Prague without having a good Catholic Church.
**Suggestions: **See if you can go to a Mass the Saturday night before your return flight. Even if it is a Roman Catholic Mass in a language you don’t understand (Spanish, Latin, German), it still counts – and I suppose it can be a beautiful experience.
Plan ahead. Here in America we can use a web site like
masstimes.org/dotNet/
Even in other countries you can find out a lot just by using a search engine.
Doing a simple google search “prague roman catholic” I came up with some information (which may or may not be correct).
English-speaking masses:
Roman Catholic Church, Church of Our Lady Victorious (the Prague Bambino), Prague 1, Karmelitská 9, Sun. at noon
(For updated mass schedule please call 257 533 646)
Roman Catholic Church, St. Thomas` Church, Prague 1 - Malá Strana, Josefská 8, Sun. 11 a.m.,
Saturday 6 p.m.
Latin:
Roman Catholic Church, St. Ignatius’ Church, Prague 2, Karlovo nám., Sunday 11 a.m.
Church of Our Lady’s Assumption, Prague 4 - Modrany, K Dolum 31/5, Saturday - 8 a.m., Last Sunday of the month - 6 p.m.
Church of Our Lady’s Birth, Prague 5 - Malá Chuchle, V Lázních, 3rd Saturday of the month at 6 p.m.
Church of St. Jacob Senior, Minor Basilica, Prague 1 - Malá Stupartská 6, every other Sunday except for summer holidays.
St. Wenceslas’ Church in Nusle, Prague 4, Vladimírova, 1st Saturday o the month at 5.30 p.m.
Church of Our Lady’s Assumption and Charles the Great on Karlov, Prague 2 - New Town, Ke Karlovu - 1st Sunday of the month 9.30 a.m.
I found the above information at the following (it may or may not be accurate).
pis.cz/a/page.php?culture=1&month=0&menu_item=1094&page_id=992