Answer

In Jain Dharma, the Mahima of Tirthankars is remembered and celebrated on many sacred days, especially:

• Kalyanak days of each Tirthankar
• Janma Kalyanak – birth of a Tirthankar
• Diksha Kalyanak – renunciation
• Kevalgyan Kalyanak – attainment of omniscience
• Nirvana Kalyanak – liberation
• Paryushan / Das Lakshan – days of deep devotion, repentance, and remembering Tirthankars’ teachings
• Mahavir Janma Kalyanak – the birth celebration of Bhagwan Mahavir Swami
• Diwali – Nirvana Kalyanak of Bhagwan Mahavir Swami

Explanation

If by “Tirthankar Mahima” you mean a specific festival or event, it depends on the Jain calendar and the particular Tirthankar being remembered.

Each Tirthankar has sacred Kalyanak days, and Jains honor their greatness through:

• puja
• stavan
• pravachan
• samayik
• pratikraman
• fasting or tapasya

Takeaway

There is not only one day for Tirthankar Mahima. The glory of Tirthankars is remembered especially on their Kalyanak days and during major Jain festivals.