Masimagam is the most important festival, which occurs in the month of Masi, Magham is the day, when the star Magham (Leonis) holds sway. In all places situated near the seacoast, sea-bath is very important for the Masi-magham festival. The deity of the local temple and the other deities from all the temples in the neighbourhood are taken in procession in a festive manner to the seashore or to the riverbanks and ceremoni-ously immersed in water with due rituals, at an auspicious moment. Simultaneously all the people attending the festival bathe in the sea. This is referred to by Sambandhar as Masi-Kadalattu (Theerthavari).
For this festival Sri Bhoovaragaswami of Sri Mushnam temple is taken in a procession to the far-distant sea-coast near Chidambaram and this procession takes a week to reach the seacoast. All the people living in the villages, on the route of the procession, participate in the festival with great joy and zeal. Likewise, in many coastal places, this Masimagham festival is being celebrated. For once in twelve years, this festival is celebrated at Kumbakonam, as Mahamagham and several lakhs of people come to take bath in the Mahamagham tank at Kumbakonam. The tradition is that the nine rivers celebrated in Hindu lore, Ganga, Yamuna, Godavari, Saraswati, Kaveri, Sindhu, Narmada, Kumari and Krishna appear in a confluence in the waters of this tank on this Masimagham day and therefore a bath in it is the most meritorious in one’s life-time. This is an age-old grand festival of All India importance.