Aranmula is a beautiful village located further inland from Chengannur, (9 km west) on the Ernakulam Quilon railroad. It is on the left bank of the Pampa river. ; it is from here that the sacred jewels of Ayyappan are taken in procession to Sabarimalai each year. Aranmula is also known for the watersports involving a spectacular procession of snake boats. It is also linked with legends from the Mahabharata. Among the Krishna temples in Kerala, the most important ones are at Guruvayur, Trichambaram, Tiruvarppu, Ambalappuzha and Aranmula.

Aranmula is one of the five ancient shrines in the Chengannur area of Kerala, connected with the Mahabharatam. (Chengannur - Yuddhishtra, Tiruppuliyur - Bheema, Aranmula - Arjuna, Tiruvamundur - Nakula and Tirukkadittaanam - Sahadeva). It has been glorified by the tamil hymns of Nammalwar of the 1st millennium CE.

The temple has four towers over its entrances on its outer wall. The eastern tower is accessed through a flight of 18 steps. Descending 57 steps through the northern tower, one can reach the Pampa river.

Legend has it that the Pandava princes, after crowning Parikshit left on a pilgrimage of India, and in Kerala, each of these brothers installed Vishnu on the banks of the Pampa and nearby places and offered worship. (Chengannur - Yuddhishtra, Tiruppuliyur - Bheema, Aranmula - Arjuna, Tiruvamundur - Nakula and Tirukkadittaanam - Sahadeva). It is said that Arjuna built this temple at Nilackal near Sabarimalai. and the image was brought here in a raft made of six pieces of bamboo to this site, and hence the name Aranmula (six pieces of bamboo).

Legend has it that Arjuna built this temple, to expiate for the sin of having killed Karna on the battlefield, against the dharma of killing an unarmed enemy. It is also believed that Vishnu (here) revealed the knowledge of creation to Bhrama , from whom the Madhukaitapa demons stole the Vedas.
There is yet another legend associated with Parthasarathy here. On the ninth dayof the battle of Kurukshetra, the Kauravas reigned supreme under the leadership of Bheeshma, when krishna motivated Arjuna to take initative and vanquish his foe. Upon his hesitating to do so, Krishna jumped down in rage, and took up his discus; seeing this sight Bheeshma surrendered to him and Arjuna beseeched him not to kill Bheeshma, as it would bave been against Krishna's vow to take up arms in his battle. It is believed that it is this image of Krishna that is enshrined here, with a discus.

The Water Carnival: This temple is located on the banks of the river Pampa. This temple is associated with water carnivals - boat race during the Onam season. A tradition of sending an offering of rice and other material required for a feast from a nearby village, on a waterboat relates to the origin of this festival and this tradition is continued even today (this is related to a legend in which a devotee fed a hungry pilgrim, who directed him to send food to Aranmula and disappeared, revealing that he was none other than Vishnu).

Snake boats accompany the sacred boat. The boat race: Snake boats from 39 Karas from Chennithala in the west to Ranni in the east participate in the watersport Vellamkali. These boats assemble since dawn and sail in pairs for about 2 hours. A snake boat is about 103 feet in length. Each boat has about 4 helmsmen 100 rowers and 25 singers. After the watersport there is an elaborate feast in the Aranmula temple.

Another festival celebrated here is the Khandavanadahanam celebrated in the malayalam month of Dhanus. For this festival, a replica of a forest is created in front of the temple with dried plants, leaves and twigs. This bonfire is lit, symbolic of the Khandavana forest fire of the Mahabharata.
The malayala month of Meenam witnesses a festival where Aranmula Parthasarathy is taken in a grand procession on the garuda mount to the Pampa river bank, where an image of the Bhagawati from the nearby Punnamthode temple is brought in procession for the arattu festival.