Goa to Kerala by Train : By far train is the most popular means to travel between Goa and Kerala. It's a 15 hours or so journey from Madgaon (MAO) to Ernakulam Jn (ERS), the main railway station for Cochin.
There are two daily express trains connecting Goa with Kerala. The first one is the Mangala Lakshadweep Express (Train No: 12618 ) from H Nizamuddin (NZM) near New Delhi to Ernakulam Jn (ERS) .
If you are heading further south of Kerala like Alleppey (ALLP), Kollam (QLN), Varkala (VAK), Trivandrum(TVC) etc, opt for Netravati Express (Train No 16345) Netravati Express connects Mumbai with Trivandrum via Goa.
Both has stop at Madgaon (MAO) of Goa. Additionally, you can board Netravati Express from Karmali (north Goa) or Canacona (south Goa).
Mangala Lakshadweep Express stops at Thivim (North Goa) also.
Other than these two daily trains you will see 3 or 4 more trains between Kerala and Goa that are weekly, bi-weekly or tri-weekly.
Select the train that suits you based on the day of travel, time and destination in Kerala. Check with irctc.co.in website for updated schedules and reservation availability.
Goa to Kerala by Flight There are no direct flights to Kerala from Goa.
By the way Kerala has three airports, to which domestic and international flights operate: Calicut International Airport (CJJ), Cochin International Airport (COK) and Trivandrum International Airport (TRV).
Your best bet is to fly to Bangalore or Mumbai and then fly to any of the 3 Kerala airports close to your destination in Kerala.
There are frequent flights from Goa to Mumbai, some decent number of flights between Goa and Bangalore. Both Bangalore and Mumbai are well connected by direct flights to Calicut, Cochin and Trivandrum.
It's a hop on hop off type journey, but that's the best available option to fly to Kerala from Goa.
Goa to Kerala by Road : National Highway 17 (NH17) running along the west coast of India connects Mumbai with Cochin via Goa. Kerala is thin long stretch of land, with its atrial highways (and rail routes too) running in the north south direction.
In about 350km of drive from the central part of Goa will bring you to the northern tip of Kerala. Cochin is a good 400km drive further and Trivandrum, the capital of Kerala is another 600km south of Cochin
Let's put it this way, Madgaon of Goa to Cochin of Kerala road distance is about 750km. Madgaon to Trivandrum the road distance is about 950km.
Goa to Kerala by Bus : This is not a very practical option, unless you are on trip to visit the many attractions located between Goa and Kerala (like Gokarna, Mysore, Mangalore etc of Karnataka).
There are no direct bus service from Goa to Kerala anyways.
However there are bus connections from the coastal towns of Karnataka from Goa. And also from Karnataka(like Mangalore or Mysore) to Kerala (like Wayanad, Kannur, Ernakulam etc).
So if your itinerary is of that nature, bus is a possible option, though it involves many connections. You'll do well, book in one of those Kerala bound trains from Goa.
By the way checkout this if still indecisive on that Goa or Kerala dilemma!
Map showing locations of Goa and Kerala along the west coast of India
1[LTT]Lokmanyatilak Terminus 2[TNA]Thane 3[PNVL]Panvel 4[ROHA]Roha 5[CHI]Chiplun 6[RN]Ratnagiri 7[KUDL]Kudal 8[[THVM]Thivim 9[KRMI]Karmali 10[MAO]Madgaon 11[CNO]Cancona 12[KAWR]Karwar 13[KT]Kumta 14[MRDW]Murdeshwar 15[BTJL]Bhatkal 16[BYNR]Mookambika Road 17[KUDA]Kundapura 18[UD]Udupi 19[SL]Surathkal 20[MAJNMangalore Jn 21[KGQ]Kasaragod 22[KZE]Kanhangad 23[CHVCharvattur 24[PAY]Payyanur 25[KPQ]Kannapuram 26[CAN]Kannur 27[TLY]Thalassery 28[BDJVadakara 29[CLT]Kozhikode 30[PGI]Parpanangadi 31[TIR]Tirur 32[KTUKuttippuram 33[SRR]Shoranur 34[TCRThrisur 35[DINR]Divine Nagar 36[AWY]Aluva 37[ERS]Eranakulam Jn 38[SRTL]Shertallai 39[ALLP]Alleppey 40[AMPA]Ambalapuzha 41[HAD]Harippadu 42[KYJ]Kayankulam 43[KPY]Karunagapalli 44[QLN]Kollam 45[VAK]Varkala 46[TVC]Trivandrum Central