Tom and Emily Kaijacks spent three days in the former Soviet state after a British ambassador spotted their work on display in a Latvian school.
The twins, whose grandfather emigrated to west Wales from Latvia, were pupils at Pennar junior school in Pembroke Dock when the opportunity came about. The school is one of 18 in Wales twinned with Latvia through an EU-funded Comenius programme of educational partnership and exchange managed by the British Council.
On his return Tom, who is now a pupil at Pembroke comprehensive, said:
"Jelgava has lots of beautiful buildings but isn't the sunniest of places and was cold.
"The Latvian children did not have as much in their school as us, and people there aren't as well off.
"We learnt a lot about the culture and also met 24 of our cousins who gave us lots of presents."
Emily was equally enthusiastic. She said: "The children all turned out to greet us and we had a go at all the things they like doing like folk dancing and singing."
Pennar junior head, Meyrick Rowlands, said: "The twins are fantastic ambassadors for their school."
Damon McGarvie, Comenius project co-ordinator, said the twins were lucky to go on the trip back to their roots.
He said: "All the children have put a lot of work into this. But Tom and Emily were lucky enough to be given the opportunity not just to see their work on display in another part of the world, but also to be made aware of just how highly it is valued."
Mr McGarvie said teachers had encouraged pupils to take part in the project.
Pennar's Latvian-bound projects in the past have focused on anything from Welsh rugby to local food recipes.
This year's theme is the town of Pembroke Dock, and while funding for the three-year initiative ends next year, Pennar and Jelgava have pledged to keep their strong ties.