Llanelli are in the FAW Premier Cup final for the first time after Mark Pritchard's header helped them see off Carmarthen in Tuesday's semi-final.
The Reds will face Newport County, who conquered Cardiff City in their tie, in next month's final after this victory at Stebonheath Park.
Striker Pritchard beat Neil Thomas from Andrew Mumford's free-kick in the first half and that proved enough.
Thomas then produced a series of great saves as Llanelli pressed for a second.
Llanelli: Ryan Harrison, Lee Phillips (capt), Andy Legg, Andrew Mumford (Craig Jones 66), Stuart Jones, David Wyn Thomas, Mark Jones, Antonio Corbisiero, Rhys Griffiths, Chris Holloway, Mark Pritchard (Nicholas Holland 90).
Subs Not Used: Ryan Lewis, Jordan Follows, Matthew Jones.
Goals: Mark Pritchard 22
Carmarthen Town: Neil Thomas, Richard Hughes, Neil Smothers, Gregg Coombes (Sacha Walters 60), Rhodri Jones, Chris Thomas, Paul Keddle, Tim Hicks (Danny Thomas 75), Paul Fowler, Jamal Easter, Nathan Cotterall.
Subs Not Used: Deryn Brace, Liam Hancock, Nicky Palmer.
Ref: Mark Whitby (Penallergaer).