Altharamood Mahavishnu temple is located at Puthenthura near Chavara in Kollam district, Kerala. The temple is dedicated to Bhagavan Srihari Vishnu. The annual prathishta maholsavam festival is held in Makaram month.
The temple is located near the Arabian Sea. There are a couple of upa devatas in the temple. The shrine has a square sanctum sanctorum with a standing murti of Vishnu Bhagavan. The shrine also has a chuttambalam, temples of upa devatas and a kodimaram.
The annual festival in the temple is famous for temple music, folk art forms, kolams, and procession.
The shrine also observes Vishu, Gokulashtami and Thiruvonam.
The annual meenottu ritual is held on Rohini nakshatra day in Malayalam Meena Masam (March - April).
The shrine observes the Karkidaka Vavu Bali and Pitru Tarpanam on Vavu or Amavasya day in Karkidaka Masam (July - August).