Head Coach Paul Osam used all 18 players at his disposal in the match, in the team's first game of two international friendlies in the space of eight days.
Germany scored twice in the opening 45-minutes through captain Torben Rhein and Emrehan Gedikli before Lasse Gunter rounded off the win in the final 20-minutes.
Speaking after the game, Osam said he was happy with how his side performed, despite the defeat.
"We done quite well, especially in defence. We had a game plan against a really good side, and we did it really well. We didn't give up a lot of chances. Their goals came from individual errors and can be easily eradicated.
"Overall we took a lot from the game, as players and staff. It was a good few days here in La Manga. It was well worth coming and playing against such high-level opposition.
"A couple of players who have not have many chances did really well. Playing against a top nation, they coped well with the demands. It was an exercise worth doing, as we can see who can play at this level."
Ireland return to action on home soil next weekend, with an international friendly against Australia in the FAI National Training Centre. Kick-off on Saturday is at 1pm.
Germany: Philipp Schultze (Tobias Werdich 60), Yassir Atty (Tekin Gencoglu 30), David Herold (Roman Reinelt 60), Luca Denk (Mesut Emre Kesik 30), Torben Rhein (capt) (Jakov Suver 60), Armindo Sieb (Leon Fust 60), David Ludwig Lelle (Winzent Suchanek 60), Arbnor Aliu (Elijah Akwasi Krahn 46), Lasse Gunter, Dennis Lutke Frie, Mehmet Ibrahimi (Emrehan Gedikli 30)
Republic of Ireland: Arlo Doherty (Daniel Rose 46), Gavin O'Brien (capt) (Fionnan Coyle 60), Adam Wells (Kevin Platon 60), Anselmo Garcia MacNulty, Oisin Hand, Kyle Conway, Colin Conroy (Jamie Doyle 60), Ben McCormack (Andrew Moran 60), Oran Crowe (Adam Wells 74), Sinclair Armstrong (Billy Vance 60), Calum Kavanagh (Dylan Gavin 60)
Referee: Victor Garcia (ESP)