International Biotech/Lab Automation Europe and Airport, Port and Terminal Security debuted at the Docklands venue last year. This year they will move to the west London facility on 25-26 November and 11 November respectively.
IIR managing director Alison Hunter said: "Olympia is a better venue for this size and shape of event. I don't think there is a better venue than Excel for big international events that need to be in London, but for a smaller show it can be quite clinical and cold."
Excel chief executive Jamie Buchan will encourage organisers to co-locate shows at the venue and will carry out a review of how the boulevard works, with a view to creating "more of a buzz for smaller shows".
"We need to make the venue cosier for shows of that size," he commented.
The defections come in the wake of a refinancing deal that has eased Excel's financial worries. Malaysian outfit Visionary Properties has taken a 75.1% controlling stake in the business in return for a £25m investment in the company.
Buchan said: "We now have a strong financial base and can go forward with a high degree of confidence."