Can I hook up an Apple Imac G3 to Airport Extreme via ethernet?

Hi,

If the router has an extra/free LAN port, and is not too far away, you could wire the G3 iMac directly.

If necessary, you could alternatively connect an appropriate Wi-Fi range extender (with an Ethernet port) operating in a wireless Ethernet bridge/client/adapter mode to the Ethernet port of the G3 iMac (the extender at https://www.edimax.com/edimax/merchandise/merchandise_detail/data/edimax/global/wi-fi_range_extenders_n300/ew-7438rpn_mini/ is merely one example; you should be able to find similar devices locally). This should allow a wireless connection to the router.

There were three grape iMac G3 models:

https://everymac.com/systems/apple/imac/specs/imac_266.html

https://everymac.com/systems/apple/imac/specs/imac_333.html

https://everymac.com/systems/apple/imac/specs/imac_dv_400.html

As Allan Jones mentioned, an AirPort card was an option (but only for slot-loading models). This was an 802.11b 11 Mbps card that has limited compatibility with modern wireless security standards. A suitable wireless Ethernet bridge device, or Wi-Fi range extender with Ethernet bridge capabilities, may be a faster replacement for wireless connections when a router requires WPA2 (or higher).

An airport card was an option for G3 iMacs. Does yours have one?

I concur that the AirPort card would be slow if present and the the bridge is the better option. On old Macs even the slow 10/100 Ethernet port should outpace 802.11b.

I mentioned it because the card would be an easy way to see if the computer sees the internet at all.