This sailing project has been implemented in Croatia's Adriatic for 19 years, organised by the Calm Seas Peace Fleet association from Vienna. It was launched in 1994 for children who were refugees in Vienna because of the war in the former Yugoslavia.
Speaking to those attending the celebration via video link, President Ivo Josipovic said the Peace Fleet had become the biggest project for socially endangered children in the world.
He said it had greatly contributed to the development of solidarity and peaceful coexistence between neighbouring countries and peoples, teaching children about tolerance, respect for diversity and each other.
He said the project was an excellent example of a positive approach to reconciliation and the building of a joint future in Europe and the region.
"Peace, tolerance and mutual acknowledgement are values which we should all nurture together and in the future we must never again allow the horrors from our history to reoccur," said the Croatian president.
Michael Fuchs of the Calm Seas Peace Fleet said participating children were taught about tolerance and reducing prejudices, adding that he was happy the project was supported by senior political representatives of Austria, Croatia, Slovenia, Bosnia, and Serbia.
Georg Diwald of the Austrian Embassy to Croatia thanked the Croatian authorities for their support in planning and implementing the Peace Fleet.
The project was supported by UN Secretary-General Ban Ki-moon in 2010.