Live lobsters are being sold on Amazon, meaning the creatures could spend up to a week in the post before reaching customers.
UK shoppers can buy one of the Canadian-caught crustaceans on the online marketplace for £46.50, including shipping.
The animals, which are available on the site through London-based third-party seller Fine Food Specialist, then face as long as a week trapped inside containers during delivery.
A number of Amazon customers have criticised the online platform in reviews for allowing the sale of live lobsters.
Susan McKenna wrote: “It is disgraceful barbarity and cruelty to send live animals through the post. I am closing my account with Amazon today.”
Jayne Mardon added: “This is quite disgraceful, to put living, feeling creatures in the post to then be boiled alive is quite horrifying.
“I won't be ordering from Amazon while they carry on with this practice.”
The news comes amid growing calls in recent weeks for the Government to ban the common cooking method of boiling lobsters and crabs alive.
A letter from campaign group Crustacean Compassion was delivered to Environment Secretary Michael Gove on Wednesday in a bid to secure protection for crustaceans in the new Animal Welfare Bill.
Signed by more than 50 campaigners including presenter Chris Packham and comedian Bill Bailey, the letter claims lobsters are “capable of experiencing pain” and should be recognised as “sentient”.
In January, Switzerland outlawed the practice of boiling lobsters alive, requiring chefs to stun the animals before killing them.
Amazon and Fine Food Specialist have been contacted by The Independent for comment.
Drogo Montagu, founder of Fine Food Specialist, told the Sunday Times here was “no evidence” to suggest lobsters could feel pain.
He said his company was trying to offer the “highest-quality products”, adding: “In some cases the finest quality is live seafood, there is a small market for these products, but it is generally people who love their food and want the very best.”
Amazon told the Sunday Times that Fine Food Specialist only used its platform as an "independent vendor" and declined to comment further.
