Bad lag when playing League of Legends?

Riot has been having issues as of late with Verizon FiOS. If you're on the East Coast and have Verizon FiOS, this is more than likely the culprit.

Depending on your ISP, and region, your packets might take a sub-optimal path. One way to work around is to use a Gaming VPN, which is basically a VPN but slightly optimized for games.

While I haven't personally used it, wtfast.com seems reasonably good at first glance.

Make sure your computer hardware and system software can RUN League of Legends (LoL)

Check League of Legends FPS Lag Fix to fix this problem.

There are a number of possible issues at play here.

Router/Wifi doesn't have strong signal, or is suffering from heavy usage. Might want to check your routers logs and see who connects to it.

If your router has usage statistics, showing bandwidth and who uses it, I would check that.

The obvious, check and make sure torrents aren't going on your network, can't tell you how many games I've played where, "WTF GODDAMNIT LAG!!!" Is followed by Steam updates, OS updates or torrent usage in background or on other systems in their network.

Otherwise, once you have checked all that, pick up WinMTR it basically automates what is called a tracert which measures latency between routing nodes to the end-point. Basically tells you where the connection is broken.

Aside from that, it might be router settings. My friends PC has a wireless card that even sitting 5ft from the router he disconnects from LAN based games. I have the same PC with a different wireless card sitting a foot further and never have any problems.(inb4 MacBook Air)

First, clean off your router/Box of Internet Glory and make sure dust hasn't settled anywhere near sensitive parts. Dust causes a LOT of overheating, and should be avoided. Next, use WTFast, and connect to the server closest to you, selecting manual setup and clicking auto select on whichever closest city. And last, don't put your Box of Internet Glory next to your TV/microwave, as these signals may affect your connection. Happy trolling!

Have you looked at your Router's Firewall Settings? Gaming is notorious for getting picked up by Firewalls. Here is a forum post recommending ports to open on your router:

https://www.astaro.org/gateway-products/network-protection-firewall-nat-qos-ips/50702-port-forwarding-league-legends.html

5000 - 5500 UDP - League of Legends Game Client

8393 - 8400 TCP - Patcher and Maestro

2099 TCP - PVP.Net

5223 TCP - PVP.Net

5222 TCP - PVP.Net

80 TCP - HTTP Connections

443 TCP - HTTPS Connections

8088 Spectator Mode

This may improve your connection significantly. There is additional testing you can do on your connection to improve performance with gaming.

Wifi may not be an issue, but to rule this out as a possible cause, you should plug your computer into the ethernet and see if there are any performance changes when you are hard-wired in.

As to whether this idea has any merit, there perhaps some background understanding of how a port, networking, and firewall work is needed:

https://serverfault.com/questions/208522/what-is-strict-moderate-and-open-nat