Bangkok has spent the past few days dealing with some of the worst flooding the Thai capital has seen in a while, and the water has brought an unexpected (and unwelcome) second problem: an exodus of cockroaches out of the drains and into homes, shops and streets.

The city endured close to 48 hours of continuous rain, with the Bangkok Metropolitan Administration reporting more than 330mm falling in parts of the capital between Thursday and Sunday. By the weekend, all 50 of Bangkok's districts had been declared flood disaster zones. Around 52,000 households were affected and nearly 4,900 people ended up in shelters, with thousands evacuated as roads and homes went under.

The insect invasion is less bizarre than it sounds. Pest-control guidance in Thailand points out that flooding pushes cockroaches out of drains and sewer systems as the water rises, leaving them scrambling for dry shelter — which often means someone's living room. Heavy rain can do the same for centipedes and scorpions. Social media filled up with clips of the aftermath, including footage from actor and content creator Martin Bravo, who filmed his group wading through flooded streets while keeping a wary eye out for anything crawling past.

For visitors, the practical takeaway is straightforward: this is not the week to arrive in Bangkok without checking conditions. Flooded roads mean severe traffic disruption, the BTS and MRT can get crowded or disrupted, and low-lying areas — including some riverside neighbourhoods and older soi in districts along the Chao Phraya — are worst hit. Monsoon-season travel to Thailand always carries some risk of this, but rainfall on this scale is exceptional even for the wet season.

If you have a trip booked, watch advisories from the Bangkok Metropolitan Administration and your airline or hotel before travelling, keep bookings flexible where possible, and consider travel insurance that covers weather disruption. Travellers already in the city should stick to elevated transport, avoid wading through floodwater (beyond the creepy-crawlies, it carries health risks), and expect slower journeys across the city until the water recedes.

The bugs, for the record, are just looking for somewhere dry — same as everyone else in Bangkok right now.