Sewage from flourishing inns and guesthouses pours, regularly untreated, out into the water dirtying the ocean and shore.
Indeed, even the nation's own particular tourism priest says he has quit swimming in the oceans near capital Colombo in view of the messy water.
More than two million guests now make a beeline for the small Indian Ocean island consistently, more than four times the number that came in 2009.
Guesthouses have sprung up to provide food for taking off quantities of guests - yet frequently with little thought for how to manage the waste they deliver.
Numerous essentially release crude sewage straight into the ocean, presenting bathers to potential wellbeing issues.
The issue is most intense only south of Colombo at Mount Lavinia, an upscale neighborhood and resort known for its "Brilliant Mile" of shoreline.
Ecological building master Mahesh Jayaweera said the sounds in Mount Lavinia were presently so dirtied that individuals ought not bathe in them.
"When you take a gander at the water you won't see it. Yet, at specific times of the year, the water in Mount Lavinia is so dingy it is more awful than taking a plunge in a cess pool," he said.
Levels of fecal pollution at Mount Lavinia are 60 times higher than greatest safe cutoff points, said Jayaweera, of Sri Lanka's University of Moratuwa.
Numerous guests are ignorant of the perils, however local people are more mindful of potential issues.
"We simply come here to play," said nearby inhabitant Harsha Swadesh, 26, getting a charge out of a session of volleyball with companions. "The ocean is harsh and it is not perfect."
Unawatuna, only south of the noteworthy port city of Galle, is advanced as an immaculate shoreline ideal for snorkeling and is popular for its coral reefs.
Yet, analysts say it is among the most contaminated, with numerous guesthouses dumping their crude sewage into the sea, particularly during the evening.
"Once in a while the current takes back the greater part of the stuff back to the shoreline in the morning and it is horrendous," said one tourism industry figure who requested that not be named.
- Tourist blast -
Tourism clergyman John Amaratunga said guest numbers have taken off following the end of Sri Lanka's 37-year-long Tamil separatist war.
"This year, our objective is 2.2 million sightseers, however we may wind up with 2.5 million," Amaratunga told AFP.
However, he surrendered unchecked development could negatively affect nature, conceding that he has quit swimming in the beach front waters off Colombo in the wake of seeing sewage streaming into it from a southern suburb of the city.
"I additionally used to go and bathe at Wellawatte... I halted it when I saw the waterway getting all the sewage into the ocean," he clarified.
He demanded the legislature was attempting to get the visitor business to get it together.
Powers have begun enrolling visitor houses to attempt to guarantee they discard their waste without hurting the earth.
Shorelines in the previous combat area in the island's north, where tourism is still moderately new, remain more clean.
Yet, Jayaweera said the circumstance was falling apart there as well - remarkably at the mainstream Nilaweli shoreline in the eastern locale of Trincomalee. Frequently hailed by travel guides as one of Sri Lanka's "absolute best shorelines", guest numbers have bounced in the previous couple of years.
Industry master and natural pro Srilal Miththapala trusts Sri Lanka necessities to roll out earnest improvements to guarantee the tourism business survives long haul.
"A couple of years back, we attempted to move the center from shorelines to eco-tourism, however most by far still visit us for our shorelines," he told AFP.
"The shorelines prevail the tourism business and that is the reason it is totally vital for us to tidy up and ensure the shorelines."