The Pre-Primary School began its journey in 2004 at the historic St Thomas’ Cathedral. Adopting elements from the Maria Montessori method, the school stands out with its unique play-and-learn model that integrates KG and nursery classes, fostering an innovative educational environment.

Nestled atop Malabar Hill, the Infant School provides a vibrant and nurturing environment for grades HKG and 1. Surrounded by lush flora and fauna, the school combines a holistic, well-structured curriculum with engaging teaching methods, fostering both academic and personal growth in young children.

The historic Junior School, housed in the former John Connon School building in South Mumbai's Fort area, combines charming heritage architecture with a dynamic learning environment. Standards 2, 3, and 4 experience a holistic education through engaging methods such as projects, excursions, exhibitions, and plays.

Founded in 1860, the historic girls’ grammar school building in Fort, Mumbai now houses Middle School, a pivotal stage for Standards 5, 6, and 7. Emphasizing critical thinking, creativity, and intellectual growth, the school combines a legacy of tradition with a modern, nurturing environment that fosters academic strength and personal integrity—preparing students for future success in the Senior School and beyond.

Senior School, standing since 1896, is a distinguished institution with a blend of Indian and Gothic architecture. Serving Standards 8 to 10, it offers an inspiring environment where academic excellence is balanced with rich cultural and athletic pursuits. The Senior School's commitment to holistic growth, intellectual curiosity, and personal development equips students to excel in board examinations and meet future challenges with confidence.

Cathedral High School, formerly known as Thomas House, is the newest addition to the Cathedral & John Connon School campus and home to the 11th and 12th standards of both the ISC and IBDP curricula. With its contemporary design housed in a beautifully restored heritage structure, the High School offers a dynamic and future-focused learning environment. It fosters academic rigour, critical thinking, and global perspectives, preparing students to thrive in higher education and beyond.