This really pretty sunset location is in Incheon Songdo Sinhang Seaside Rest Area 송도신항바다쉼터 (I can’t find the official English translation of this place, so the name is translated by me, it might be different from the official translation.)
I went here mid April 2017, but because sunset was at almost 7pm, and this place got some military significance, so it closes every day before 6pm, so I didn’t manage to view sunset here.
It looks like this outside the gate, I almost did not know this is the place when i got there
I went there and then compared the location with the clip from the drama, and the filming should have been done in the part close to the entrance here
Along the way you can see Koreans fishing there，I was there on a weekday, there weren’t many people and it was really relaxing to be there.
仁川一號線Campus Town站(캠퍼스타운역)一號出口換乘91號巴士到達總站松島Sports Centre(LNG棒球場)송도스포츠센터(LNG야구장)下車(十個站車程25分鐘)，下車以後沿著巴士進運動中心的原路，回頭走到大馬路，然後轉右，再過馬路就可以看到。
From exit 1 of Campus Town Station of Incheon Line 1, change for bus 91 (10 stations and about 25 mins) and get off at Songdo Sports Centre(LNG Baseball Field), and then walk back along the way bus came into the Sports Centre to the main road, turn right and then walk across the road.