The most important festival at Sabarimala temple is Makara Vilakku. It is a seven-day festival commencing on the day of Makara Sankranthi, the day on which the sun is in summer solstice. It was on this auspicious day, the idol of Dharma Sastha was enshrined in the temple. The annual celebration of Makara Vilakku is commemorative of this sacred event.

The jewellery to adorn the Deity (Thirivabharanam) on the occasion of the festival is brought from Pandalam Palace in a ceremonial precession, which starts from Valiya Koyikkal Sastha Temple at Pandalam three days prior to Makara Sankranthi. Thousands and thousands of devotees line up on either side of the route along which the procession proceeds, looking forward to the approach of the grand gala. The boxes containing the sacred jewellery are placed on the head of an oracle. He appears to be oblivious of his physical existence and marches on dancing hysterically. Still the boxes remain on his head as if glued there. Relaxing in a few temples enroute, the precession reaches Sabaripettam in the evening on the crucial day. The procession is accorded a ceremonial welcome and led to Sannidhanam accompanied by lights and music. Curiously enough, a kite appears in the sky and hovers around the boxes of jewellery. At the sight of the procession, rapturous shouts go up from the waiting crowd, along with the air-splitting sound of hundreds of gun shots.

The jewellery consists of diamond diadem, golden bracelets and necklaces studded with precious gems, Lord's swords, silver arrows and images of elephant, horse and leopard made of gold. The radiance emanating from the Deity bedecked with these sacred ornaments, surpasses the brilliance of thousands of conglomerated stars.

Now every eye turns to the north-east horizon to witness the peerless phenomenon, the appearance of 'Makarajyothi " another spectacular scene which leaves an indelible impression in the hearts of the devotees. On seeing this celestial splendor, in the midst of the spontaneous cries of 'Swamiye Saranam Ayyappa' from millions of throats, one experiences a rare feeling of ecstasy and a unique sense of accomplishment.

Poojas and other ceremonies connected with the celebration of Makara Vilakku are performed on the ‘Manimandapa’ (sacred platform) near the Devi shrine. A picture of Sastha as riding on a leopard's back is depicted on this platform.

After the pooja's, Malikappurath Amma is mounted on an elephant's back and taken in Procession, accompanied by torch-bearers, drummers, buglers etc. to Pathinettampadi. The procession stops there and shouts a call for hunting (Vettavili). Then the procession returns circumambulating the main temple.

The festival lasts for seven days and ends with the ritual known as 'Guruthi " an offering conducted to propitiate the gods and goddesses of wilderness. No one remains in the temple premises after the performance of Guruthi.

Witnessing the festival of Makara Vilakku and related ceremonies is considered to be very auspicious, There are many stories prevalent revealing the greatness of the festival of Makara Vilakku.

Other important festivals conducted are Onam, Mandalapooja and Vishu Vilakku. Temple will be open for worship at the beginning of the Malayalam Months.