He spent the next two seasons learning from former Manchester United, Luton Town, Aston Villa and Coventry City goalkeeper Les Sealey and sitting in the pecking order behind Craig Forrest, Bernard Lama and Shaka Hislop. With first team opportunities limited, Bywater joined Wycombe Wanderers on loan in September 1999, making two appearances, and then went to Hull City on loan in November 1999, making four appearances. A broken leg for Shaka Hislop meant a debut for Bywater at the age of 19 against Bradford City in February 2000, in a game that saw Bradford score four times but which West Ham eventually won 5–4. Bywater also appeared in the final three games of the 1999–00 season, against Arsenal, Sunderland and Leeds United and made a single appearance in the following season against Bradford in February 2001.