The duo are part of a squad of 44 athletes from six different sports that Great Britain will send to the festival in Azerbaijan, which will start on July 21 and run through to July 27.
It will be a chance for British age group breaststroke record holder Williams to test himself on the international stage.
Meanwhile, it will be Freeman’s second chance in the space of a few weeks to challenge herself against Europe’s best. She has just returned from the European Junior Championships in Kazan where she made the 200m butterfly final, despite being the youngest in the field.
The European Youth Olympic Festival provides crucial multi-sport event experience for young athletes, with more than 40 athletes graduating from a summer EYOF with Team GB going on to compete at the Beijing 2008, London 2012 or Rio 2016 Olympic Games.
The likes of Becky Adlington, Pete Kennaugh, Sally Conway and Nile Wilson all had their first taste of an Olympic-style event at an EYOF before winning an Olympic medal at senior level.
Baku is the 15th edition of the summer EYOF and Team GB have enjoyed a successful Games at each, with 10 medals won two years ago in Gyor, Hungary and at least 20 medals in each of the previous 13 festivals.
Leading the Team GB delegation as Chef de Mission at Baku 2019 will be Elaine Skilton, who acted as Deputy Chef de Mission for Team GB at last year’s Youth Olympic Games in Buenos Aires.
Speaking at the team’s announcement, Skilton said: “Wearing the Olympic rings for the first time and competing for your country is always a huge honour and I’m sure today is a proud moment for each of the 44 selected athletes and their families. Baku 2019 is set to be a great event and we have a very talented group of British athletes coming together to form Team GB for this Festival.
“European Youth Olympic Festivals are fantastic for the next generation of British Olympic sporting stars, providing an opportunity to compete internationally, experience the unique world of multi-sport events and be part of Team GB.
“The British Olympic Association is already underway with planning for Paris 2024 and no doubt a number of these athletes will already have their eyes set on those Games. Hopefully Baku 2019 can act as a great springboard for them as they develop and move through their sporting career towards.”