The annual Seminar on Theory of Coding "Professor Stefan Dodunekov" took place from November 8th to November 11th, 2018 at the "Bolyarski Meridian" Hotel in Veliko Tarnovo (Bulgaria). This is the thirtieth anniversary edition of the international seminar. The seminar is also a session of the "Mathematical Foundations of Informatics" section of IMI-BAS. 30 years ago, in 1988, the department of the section in Veliko Tarnovo was created under the name of Laboratory of Mathematics and Informatics. In the first years, the Laboratory Mathematics and Informatics was in the "Akademiya" Association with Director Iliyan Nikolov, along with 4 other units of the Bulgarian Academy of Sciences, and subsequently moved to IMI-BAS. The Scientific Program on November 9th and 10th included papers, presentations of dissertations and discussions. The National Seminar on Theory of Coding was founded in the 1980s by Acad. Stefan Dodunekov and since then it is held annually at the end of the year. From 2014, the seminar also bears the name of Academician Dodunekov, who was director of IMI-BAS from 1999 to 2012 and chairman of the Union of Mathematicians in Bulgaria from 2001 to 2012. The academic studies of Stefan Dodunekov on coding theory are well-known in the scientific community. The theory cover a wide range of problems - from fundamental tasks, meaning to abstract algebra and geometries, to purely applicable problems in the field of data protection. Acad. Dodunekov is one of the leading scientists in coding theory in the world.