Certina DS from around 1960. Here an early edition with caliber 25-45 movement. The no-date automatic version here is not very common. Most are automatic with date or manual with or without date.
This old Seiko diver is still going strong. I took it swimming on my recent vacation to Norway.
This is a Seiko 6309-7040 from 1977, also known as “turtle”.
I wouldn’t recommend taking a vintage watch swimming unless you have had it serviced and pressure tested in recent years 😅