Coins have been dated for centuries, so it all depends on what you mean by "dated". One of the best resources on dating in numismatics is the two-volume book "Tempus In Nummis" by James D. Sweeny.
Consider the following Georgian coin which is dated, in the Georgian "Paschal cycle":
Obv: Bagratid royal emblem in the form of a standard; Georgian initials to left and right: ႧႰ=ႧამაႰ (T'amar) and ႣႧ=ႣავიႧ (David); Georgian initials on top left and top right: ႵႩ=ႵორონიႩონსა (Koronikonsa/Year); Georgian initials on bottom left and bottom right: ႯႩ=420
Rev: Christian inscriptions in arabic script; countermark #4
ملكة الملكات (
Malekat al-Malekaat(s); Queen of Queens)
جلال الدنيا و الدين (
Jellal Al-Dunya Wal Din; Glory of the World and Faith)
تمار ابنة كوركى (
Tamar Ibnat Kurki; T'amar daughter of Giorgi)
ظهير المسيح (
Zahir Al-Massih; Champion of the Messiah)
The Georgian year is encoded using the "Paschal cycle". This dating system is based on the creation date being March 22, 5604 BC. From this date, they ran through a 532-year cycle. So, Year 1 was March 22, 5604 BC for the 1st cycle. And the 13th cycle's Year 1 was March 22, 781 AD. For years 346 to 532, add 780 to obtain the corresponding year in AD. The year starts off at March 22nd for each AD year. So, 420 + 780 = March 22, 1200 AD.
Another example is the dating of coins using regal years, and the Byzantine coinage is an example of that:
Byzantine Empire: Justinian I (527-565) Half Follis, Regal Year 12, Constantinople (Sear-165)
Obv: D N IVSTINIANVS P P AVG. Helmeted and cuirassed bust facing, holding globus cruciger and decorated shield; cross right in field.
Rev: Large K between ANNO - XII, cross above; E below.
The Chinese also minted dated coins and an example of that can be seen here:
Imperial China, Southern Song: Kai Xi (1205-1207) FE 2 Cash, Tongan Mint (Hartill-17.529)
Emperor Ning Zong (1195-1224)
Obv: 開(开)禧通宝 Kai Xi tong bao
Rev: 同 Tong above. Tongan mint, Anhui. Numbers for the year of casting below. 三 san (Year 3 - 1203)
And of course, the earliest Islamic coins where also dated as well, like the following:
Umayyad Caliphate: Anonymous (738 AD) AE Fals, Wasit Mint (Walker-941; Lavoix-1522; Nützel 2049-2050; Album-205)
Obv: Within a double circle, لا اله الا الله وحده لا شرك له (
There is no God but Allah alone. There are no others with him); five annulets enclosed in outer margin.
Rev: At center, محمد رسول الله (
Muhammad is the apostle of Allah); in margin, بسم الله ضرب هذا الفلس بواسط سنة عشرين ومائة (
In the name of Allah this fals was struck at Wasit in the year 20 and 100); double outer margin enclosing five annulets.
And finally, a more "normal" coin which is what I think you meant, but that is a bit biased:
Hungary: Ferdinánd I (1526-1564) BI Denár (Huszár-935, Réthy-40, Unger-745a)
Obv: FERDINAND · D · G · R · VNG ✶ 1537 ✶; Quartered Coat of Arms (strips, double cross, leopard heads, Bohemian lion), at the heart , Austrian Shield
Rev: PATRONA · ✶ · VNGARIE; Virgin Mary, crowned, enthroned facing, holding infant Jesus; across field, K-B (Kremnitz)