Relish is to deliver 4G routers to customers on the day they order, if the order is received before 12 noon.
According to Bridget Lorimer, Head of Brand at Relish, consumers have come to expect "instant convenience" from service providers.
Indeed, she said this is the case across a wide range of services, from Amazon deliveries and taxi companies to restaurant food at home.
"We see no reason why broadband shouldn't be the same," Ms Lorimer commented.
"We were the first to bring Londoners a broadband service that didn’t require them to pay for landlines they don’t want or need, and we are proud to be the first to bring same day broadband to the market.
"With our new service we are enabling Londoners to order in the morning, and 'Netflix and Chill' the same evening."
Ms Lorimer added that the fact "time-poor" Londoners have been forced to spend time off work to wait for broadband is "absurd".
Figures from Relish show that nearly four in ten people in London have had to stay off work for anything from half a day to more than two days so they can have the internet installed at home.
Research also showed that almost six in ten have had to wait between three days and a month for broadband to be installed.
The announcement comes soon after Relish was honoured at the Internet Service Providers' Association's (ISPA) 18th Annual UK Internet Industry Awards.
Relish won the Best Consumer Broadband award largely on the strength of its "great and transparent service".
The ISPA also noted that judges were particularly impressed with its "focus on a customer base often ignored by other providers".