The English language is the centerpiece of our curriculum which is based according to the UK Key Stages. Key Stage 1 refers to Year 1 and 2 of the Primary Section, Key Stage 2 refers to Years 3, 4, 5 and 6, Key Stage 3 refers to Years 7, 8 and 9, whereas Key Stage 4 refers to Years 10 and 11. Key stage 5 refers to Years 12 and 13.

As in most UK schools, students from Key Stages 1 to 4 have English Language and Mathematics every day and are compulsory subjects which all students must attend.

Being an international school we heavily promote the learning of foreign languages and we offer German, Italian and Croatian as electives with the possibility of other languages being incorporated. Students can choose one foreign language to study as early as Year 2. Other subjects include PE, Drama, IT, with electives in Croatian History and Culture for foreign students, Dance, Swimming, Basketball, Football and other sport activities.

A core part of our Primary curriculum is the highly regarded International Primary Curriculum (IPC). This is a thematic based framework with exciting new age unit topics developed around Science, Health, History, Geography, Art, Music and International Mindedness. These units are taught in five week blocks and are developmental.

Key Stage 3 in the UK comprises of Years 7, 8 and 9. This is defined as Lower Secondary. At BISZ, students will study English, Maths, Science, History, Geography, a choice of at least one Modern Foreign Language (Croatian, Italian, German and French), Art and Design, Music, Physical Education, Citizenship and ICT (Information and Communication Technology).

Key Stage 4 is Middle Secondary and is made up of Years 10 and 11 during which students at BISZ will be able to study a range of subjects offered at the IGCSE/GCSE level. These include core subjects which are English, Maths and Science, and the foundation subjects ICT (Information and Communication Technology), Physical Education, Citizenship, and elective subjects taken from The Arts, Humanities and Modern Foreign Languages.

For Years 12 and 13 the students at BISZ will choose which subjects to study at the AS level (in Year 12) and A2 level (in Year 13). Students choose subjects specifically targeted towards the University Course they wish to pursue as a career path. This is considered as Upper Secondary - Key Stage 5.