The benefits of tea to human health have long been recognised due to the strong association of tea with long life in many cultures. Catechins are a class of flavonoids present in the greatest abundance in the leaves of tea trees. Their antiviral properties have been the focus of recent interest including their potential to inhibit the propagation of the human immunodeficiency and the influenza viruses. Their ability to inhibit the influenza virus, in particular, has been stimulated by the rise in the number of circulating strains resistant to the current antiviral inhibitors. The mechanism of their mode of action, however, is not well understood. We have studied the antiviral potential of these compounds against circulating strains of influenza virus using a combination of sialidase activity assays with confocal microscopy, sialidase inhibition assays and computer-based molecular docking. The antiviral properties of three catechins found in green tea, epigallocatechin-3-gallate (EGCG), epicatechin-gallate (ECG) and catechin-5-gallate (C5G), were studied following their addition to influenza infected MDCK cells employing a sialidase activity assay in conjunction with confocal microscopy. Treatment of already infected MDCK cells revealed their antiviral activity when added within 1h post infection, but that this decreased when added at later time points (2h or 4h). All three compounds were shown reduce the sialidase activity of the viruses at concentrations above 50µM and completely at 150µM. Their IC50 values were approximately 30µM as determined by a plaque assay. Companion molecular docking studies showed that the compounds all bound to the active site of influenza neuraminidase in the vicinity of the 430-cavity, a region adjacent to the 150-cavity targeted by oseltamivir and zanamivir that contains the majority of known resistance mutations. They therefore offer potential as the basis for newly designed antiviral inhibitors to influenza viruses that overcome these resistance limitations.