On 11 February 1963, the Beatles recorded ten songs during a single studio session for their debut LP, Please Please Me. The album was supplemented by the four tracks already released on their first two singles. Martin originally considered recording the Beatles' debut LP live at the Cavern Club, but after deciding that the building's acoustics were inadequate, he elected to simulate a "live" album with minimal production in "a single marathon session at Abbey Road". After the moderate success of "Love Me Do", the single "Please Please Me" met with a more emphatic reception. Released in January 1963, two months ahead of the album of the same name, the song reached number one on every chart in London except Record Retailer, where it stalled at number two. Recalling how the Beatles "rushed to deliver a debut album, bashing out Please Please Me in a day", AllMusic's Stephen Thomas Erlewine comments, "Decades after its release, the album still sounds fresh, precisely because of its intense origins." Lennon said little thought went into composition at the time; he and McCartney were "just writing songs a la Everly Brothers, a la Buddy Holly, pop songs with no more thought of them than that - to create a sound. And the words were almost irrelevant."

Released in March 1963, the album initiated a run during which eleven of their twelve studio albums released in the United Kingdom through 1970 reached number one. The band's third single, "From Me to You", came out in April and was also a chart-topping hit, starting an almost unbroken string of seventeen British number-one singles for the Beatles, including all but one of the eighteen they released over the next six years. Issued in August, the band's fourth single, "She Loves You", achieved the fastest sales of any record in the UK up to that time, selling three-quarters of a million copies in under four weeks. It became their first single to sell a million copies, and remained the biggest-selling record in the UK until 1978, when "Mull of Kintyre", by McCartney's post-Beatles band Wings, surpassed it in sales. Their commercial success brought increased media exposure, to which the Beatles responded with an irreverent and comical attitude that defied the expectations of pop musicians at the time, inspiring even more interest. The band toured the UK three times in the first half of the year: a four-week tour that began in February, the Beatles's first nationwide, preceded three-week tours in March and May–June. As their popularity spread, a frenzied adulation of the group took hold. Greeted with riotous enthusiasm by screaming fans, the press dubbed the phenomenon "Beatlemania". Although not billed as tour leaders, the Beatles overshadowed American acts Tommy Roe and Chris Montez during the February engagements and assumed top billing "by audience demand", something no British act had previously accomplished while touring with artists from the US. A similar situation arose during their May–June tour with Roy Orbison.

McCartney, Harrison, Swedish pop singer Lill-Babs and Lennon on the set of the Swedish television show Drop-In, 30 October 1963 In late October, the Beatles began a five-day tour of Sweden, their first time abroad since the final Hamburg engagement of December 1962. On their return to the UK on 31 October, according to Lewisohn, "several hundred screaming fans" greeted them in heavy rain at Heathrow Airport. Around 50 to 100 journalists and photographers as well as representatives from the BBC also joined the airport reception, the first of more than 100 such events. The next day, the band began its fourth tour of Britain within nine months, this one scheduled for six weeks. In mid-November, as Beatlemania intensified, police resorted to using high-pressure water hoses to control the crowd before a concert in Plymouth.

Please Please Me maintained the top position on the Record Retailer chart for 30 weeks, only to be displaced by its follow-up, With the Beatles. On 22 November EMI released With the Beatles to record advance orders of 270,000 copies, and the LP topped a half-million albums sold in one week. Recorded between July and October, With the Beatles made better use of studio production techniques than its predecessor. It held the top spot for 21 weeks with a chart life of 40 weeks. Erlewine described the LP as "a sequel of the highest order – one that betters the original". In a reversal of then standard practice, EMI released the album ahead of the impending single "I Want to Hold Your Hand", with the song excluded to maximise the single's sales.The album caught the attention of music critic William Mann of The Times, who suggested that Lennon and McCartney were "the outstanding English composers of 1963". The newspaper published a series of articles in which Mann offered detailed analyses of the music, lending it respectability. With the Beatles became the second album in UK chart history to sell a million copies, a figure previously reached only by the 1958 South Pacific soundtrack. When writing the sleeve notes for the album, the band's press officer, Tony Barrow, used the superlative the "fabulous foursome", which the media widely adopted as "the Fab Four".