Travelers treat public Wi-Fi as one thing and are then puzzled when it behaves inconsistently. Airports, hotels and cafes solve different problems, and their networks reflect those differences.
The captive portal is the first obstacle
Most public networks intercept your first request and redirect it to a login page, which is how they collect acceptance of terms or a room number.
Devices that expect encrypted connections often fail silently against that interception, which is why a phone shows connected while nothing loads until the portal appears.
Custom secure DNS settings and always-on VPN clients frequently prevent the portal from displaying at all, and turning them off briefly to log in is the usual remedy.
Airports are built for many short sessions
An airport network serves an enormous number of devices, most for a short period, with unpredictable clustering at gates. It is engineered for connection count rather than sustained throughput.
Bandwidth is often limited per device and sessions may be time-limited, since the aim is to give everyone basic access rather than to give anyone a lot.
Video calls and large uploads suffer particularly, because they need consistent capacity in exactly the way the design does not prioritize.
Hotel networks are shaped by the building
A hotel serves fewer devices for far longer, but the physical structure works against it. Concrete floors, elevator shafts and dense walls attenuate signal severely.
Coverage therefore depends heavily on where access points were installed, which is why one room is fine and the room above it is not. Older properties retrofitted after construction have the most variable results.
Many hotels also segment guest traffic and offer a paid tier with higher throughput, so the free tier may be deliberately constrained.
Filtering explains most blocked applications
Public networks commonly block certain ports and protocols to limit abuse and manage traffic, which can break VPN clients, mail protocols and some business tools.
Those choices vary by operator, and there is rarely a message explaining the block, so a tool that fails on one network and works on the next is usually encountering a policy difference.
What actually works while traveling
A cellular hotspot avoids all of it, and for anything sensitive or bandwidth dependent it is more reliable than any public network. Roaming and data costs are the tradeoff, and plans vary.
Where public Wi-Fi is the only option, using a VPN once connected, avoiding unnecessary account logins and downloading what you need before departure remain the practical habits.