What time of day or even side of the island is best to catch the following? I already know month time frame. But after trying and trying with kids islands its getting old.

Vampire Squid

Gigas Giant Clam

Spiny Lobster

Giant Isopod

the gigas giant clam is around all day

the isopod is around most of the day (9pm - 4am, 9am - 4pm)

the vampire squid is around at night (4pm - 9am)

the best time to look for them is 9pm - 4am because all three will be out. all three of them are very rare and swim very fast. you'll know you've found one because it'll swim just as fast as you do. the way to catch them is to corner them so they have to swim back towards you, or swim slowly without pushing the A button to sneak up on them.

the spiny lobster is available 9pm - 4am October - December