The London Evening Standard says the Hammers boss was at the Valley on Saturday lunchtime watching Charlton's 2-2 draw with Wigan, where West Ham loanee Josh Cullen played 90 minutes and Moyes got a look at highly rated Wigan left-back Antonee Robinson.
Robinson is expected to move this summer having seen a £10million move to AC Milan fall through in January.
Following his trip to south London, Moyes headed west to Loftus Road for QPR's 4-3 win over Millwall. West Ham are one of many clubs interested in forward Eberechi Eze and Moyes continued to keep a close eye on full-back Ryan Manning. Both scored in the London derby.
Moyes is keen to press ahead with his plans to bring young, hungry players into the club over the summer after the Hammers all but secured their Premier League status for another year by beating Watford on Friday evening.