Bacteria can adhere to various surfaces and rapidly proliferate, forming biofilm. Biofilm can serve as a reservoir of spreading the bacterial cells and can be crucial problems for public health. To prevent bacterial contamination on surfaces, antibacterial materials and their coating methods have been studied. Herein, we synthesized an antibacterial material by introducing catechol group into brown algae (Fucus vesiculosus)-derived fucoidan via amide coupling. Spray coating method, which can be applied to large surface area, was devised through the crosslinking between ferric ion and catechol-conjugated fucoidan. The catechol-conjugated fucoidan (FD-C) was applied to stainless steel and titanium dioxide and the fucoidan-coated substrates were characterized by using ellipsometer, contact angle goniometer, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. We demonstrated that the FD-C coated substrates have antibacterial property, compared to bare substrates, using E. coli. We also applied the spray coating of fucoidan to straps of train and confirmed the antibacterial effect of the spray coating. We think this approach can be utilized for antibacterial coatings for equipment in public transportation to prevent infectious harmful substances from spreading.