Good business communication aims to ensure that the recipient of the message, either written or oral, fully and unambiguously understands the message. Since English is the official language of communication in maritime industry, acquisition of English is the key to achieving a good and successful communication in business, avoiding thus any misunderstandings or doubts. In everyday communication on board ships as well as in communication ship-to-shore or ashore, terms specific to maritime profession are used. Professional terminology should be well known to all participants, however, certain terms used in maritime business communication are sometimes challenging. There are often issues with groups of words that are always used together and whose literal meaning differs from the meaning of each word respectively. These sets of words are called idioms. In order to recognise them, it is necessary to possess a good understanding of the language and to understand their application in business communication. The aim of the thesis is to find out the extent to which students of the University of Dubrovnik (Maritime Department) recognise selected English idioms used in maritime business communication. For this purpose, a survey to explore understanding of idioms among students of the Maritime Department was carried out (N = 40). The survey was conducted by using an online survey questionnaire. Results of the research have shown that the students are to a large degree familiar with and understand the meaning of selected English idioms.