[1] The temple is dedicated to the worship of deity Vishnu in the form of Janardanaswamy, locally known as Varkaleswara (the lord of Varkala).

[citation needed] According to the temple legend, attracted by the music from Narada’s veena, Vishnu followed him and reached Satyaloka.

The devas asked where they should do the penance, and Brahma replied that the place would be where Narada’s cloth had fallen: Varkala.

Another states that long ago, Brahma came to earth to perform a yajna (fire sacrifice) in the location of Varkala.

Varkala, a seaside suburban town of Thiruvananthapuram, is also known as Janardanapuram or Udayamarthandapuram or Balit, and is a sacred pilgrim center.

It is believed that praying at the temple and taking a bath at the nearby Papanasam beach will wash away one's sins.

[citation needed] The presiding deity of this temple, Janardanaswamy, is found standing and facing east.

In the south-western corner and on the north-eastern side of the outer enclosure are the shrines of Sasta and Shiva with Nandi.

Aspects of the temple—including the circular "sanctum sanctorum" surmounted by a conical dome of copper sheets, the square mandapa with wooden carvings of Navagrahas on the ceiling and copper-plated roof, the quadrangular enclosures (prakaram) around them, and a hall containing a Bali Pitha in front of the inner temple—are characteristic features of Kerala architecture and the highly embellished temples of South India.

The temple has an ancient bell removed from a shipwreck, donated by the captain of a Dutch vessel which sank near Varkala without casualties.

[clarification needed] One of the inscriptions indicates that the temple was partially renovated during the reign of Umayamma Rani who ruled this region in 1677–84 CE.

Besides the sea view, there is also the backwater journey by canal hewn out of the tremendous heights of hills on either side of it.

The vegetation on either side of the canal has given rise to a series of springs from which sparkling water gushes throughout the year.

Every year, in the Malayalam month of Meenam (March–April), a ten-day Arattu festival is celebrated at the Janardanaswamy Temple in Kerala's beach town of Varkala.

The festival starts with a Kodiyettam flag hoisting ceremony, and ends with a procession of five decorated elephants through the streets.

During the fourth and fifth days of the festival, the celebrations include all-night performances such as traditional Kathakali dancing.

The arattu (holy bath) of the deity is conducted on Uttaram day in the Arabian Sea behind the temple.

Apart from this festival, the days of the appearance of Vishnu's avatars (e.g.: Rama Navami, Ashtami Rohini, Narasimha Jayanti), Karkidaka vavu (Amavasya day in the month of Karkidakam, which comes in July or August), and Vaikuntha Ekadashi are also celebrated in the temple.