Chellanam formed the southern border of the pre-colonial Kingdom of Cochin.

In 1510, Goa was captured by the Portuguese general Alfonso Albuquerque from the Adil Shah dynasty of Bijapur, and Portuguese rule was established. The Kudumbis, along with Gouda Saraswat Brahmins (Malayalam: ഗൌഡ് സാരസ്വത്), Daivajnas and Vaishya Vanis who wanted to preserve their religious and cultural identity, migrated from Goa along the west coast of India, primarily through sea voyages.

Some of the groups that fled Goa landed in coastal districts of state of Karnataka, that is, the Uttara Kannada, Dakshina Kannada and Udupi districts, and some groups voyaged further to Kerala. One of these first exodus groups landed on the island of Cherai, Kerala. They slowly migrated southwards from Ernakulam and settled in coastal areas. They were experts in paddy cultivation, especially in the low-lying fields of the Kerala backwaters, and they pioneered cultivation of the well-known "Chettiverippu" strain of paddy rice, brought from Konkan.

A group of Kudumbis may have migrated to Chellanam at the invitation of a Maharaja and on arrival been given (free of tax) a coconut garden and land to grow rice. In return they were required to supply Avil to the palace and temple free of cost. The main agricultural laborers of Chellanam have been from the Pulaya and Kudumbi castes. It is also observed that during the Portuguese period, a lot of people converted to Christianity.

On 24 May 2010 residents of Maruvakad, staying near Thiruhridaya Chapel, just 100 meters from Velankanni Matha Pilgrim Center; dug an old well which is to be believed that, it was built and used by Dutch Army around 200 years ago.This will help and will be a new resource for drinking water. Water is the most precious element for the people of Chellanam.

The Maharaja of Kochi had a marine fleet which had a captain named Thobias Cappithan. When he won a battle he was presented with a piece of land called "Chellavanam". It was a vanam (forest) that was not inhabited normally at that time, but he settled there with his family. He had four sons; one stayed near a banyan tree (aal maram) and became known as Alumkal family, another stayed at Valiyaparambu and became Valyaparambu family, the son who stayed near "Kalam" became Kalathumkal family and another near a statue of Holy Cross and later his descendants came to be known as Kurisingal family. Chellavanam now is called Chellanam.
 

Chellanam is on a narrow landform about 10 km in length, starting from St. George Church at the southern end at the northern border of Pallithode village and Kattiparambu (near Thoppumpady). At the northern end it has a width of 250 metres, accommodating in between the villages of Chellanam, Maruvkad, Chalakadavu, Kandakadavu, Puthenthodu, Kannamaly, Cheriyakadavu and Kattiparambu. The landscape is filled with bungalows and courtyards. There was a canal (azhi) passing through this place to the sea which later closed naturally and formed in a place called Andhakaranazhi in Alappuzha district. Chellanam comes under kochi legislative assembly and Ernakulam loksabha constituency. The local self-administration body is Chellanam grama panchayath. SH 66 also called Alappuzha Arthunkal Kochi road passes through Chellanam.

Chellanam Ezhupunna Eramalloor road connects Chellanam to NH 66 at Eramalloor, a developing suburb of kochi. Eramalloor is the southernmost suburb of kochi. Ezhupunna railway station having stops for few passenger trains is located on this road and is the very nearest railway station. Chellanam south Neendakara junction on SH 66 is some 4.5 km from Eramalloor jn. The main portion of Chellanam village consists of pokkaly fields. According to the traditional practice, the fields used to be prepared for paddy cultivation from the Vishu day, falling in April every year. The land had to be dried under the hot sun for almost a month, by which time the salt content left over from the prawn farming would be ready to be washed off by the first rain of the monsoon season.Chellanam harbour, one of the finest picturesque harbours in kochi is located at south chellanam. Chellanam harbour is one of the main fishing centres in Kochi. Government of kerala as proposed funds for the next phase development of harbour.