The construction was completed in 1866. The organ was built by one of the best organ builders of that time H.A. Contius. The instrument with 38 stops was officially handed over to the church in 1779. During the 19th century the instrument was repeatedly enlarged, in 1885 – up to 131 stops.

The organ has 131 registers, 4 manuals and over 7000 pipes. Concerts of organ music are regularly held in the church. The interior decorations of St. Trinity Church are rich and ornate. Also nowadays the organ is one of the largest in Europe. The interior of the church displays splendor typical of rococo style.

Inside the church you can see also a plaque dedicated to Finnish Jaegers who gave the oath of loyalty to the government of the newly established independent Finland in 1918 in this Liepāja church. Use the opportunity to climb up to the top of the church tower (55 meter) revealing a breathtaking panorama of Liepāja!